It's probably overreaching but there were some little egg references — OVULES, BELUGA (roe), NESTERS, um, OVID — that made me wonder, but maybe this great solve just made me loopy.
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Those molecules enter the plant's ovules (part of their ovaries where they are arranged and grow into fibers) in two different ways: by osmosis and through a gate of sorts that recognizes and allows the sugar in.
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Medusagyne and Quiinoideae have two ovules per carpel. In Testulea and in a clade of four genera in Sauvagesieae (Godoya, Rhytidanthera, Krukoviella, and Cespedesia), the number of ovules is 100 to 200 per carpel. For the remainder of Sauvagesieae, except Euthemis, and for Philacra and Luxemburgia, the number of ovules per carpel ranges from four to 50. Euthemis has two ovules per carpel.
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In Ochneae, Lophira has 4 to 50 ovules per carpel. In the subtribes Elvasiinae and Ochninae, the number of ovules per carpel is one.
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"Elkinsia gen. nov., a Late Devonian gymnosperm with cupulate ovules." Botanical Gazette, 150: 170-189. and they have the most primitive features, most notably in the structure of their ovules.
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The ovary of macadamia contains two orthotropous ovules at anthesis.
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The small ovules (fossil genus Callospermarion) with the characteristic secretory structures have an integument that was only fused to the nucellus in the basal part of the ovules and so superficially resemble medullosalean ovules. Unlike the Medullosales, the ovules appear to be bilaterally symmetrical, although details of the vasculature suggest they were in fact evolved from plants with radially symmetrical ovules. The apical part of the nucellus has a lagenostome-like projection, which breaks down to form the pollen chamber. The full ontogeny of these ovules has been worked out in some detail and seems to be essentially similar to that seen in modern-day gymnosperms, including the use of a pollen drop to help capture and draw the pollen into the pollen chamber and a pollen tube to deliver the generative nucleus.
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Ovules are produced on the adaxial surface of the cone scales.
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As the Lyginopteridales are the earliest-known gymnosperms, and the development of ovules was one of the key innovations that enabled seed plants eventually to dominate land vegetation, the evolution of lyginopteridalean ovules has attracted considerable interest from palaeobotanists. The most important work on these early ovules was by the British palaeobotanist Albert Long, based mainly on early Mississippian, anatomically preserved fossils from Scotland (UK). Some of the earliest ovules (e.g., Genomosperma) consisted of a nucellus (the equivalent of the sporangium wall) surrounded by a sheath of slender axes known as a pre-integument.
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With the exception of flowering plants, seed plants produce ovules and pollen in different structures. Strobili bearing microsporangia are called microsporangiate strobili or pollen cones, and those bearing ovules are megasporangiate strobili or seed cones (or ovulate cones).
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The development of the ovules appears to be similar to that of Cycadeoidea.
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Umkomasia has helmet like cupules around ovules born in complex large branching structures.
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The number of locules in the ovary is highly variable, usually from two to five, but sometimes as many as fifteen. The placentation is apical, with a pair of ovules hanging by their funicles from the top of each locule. Often, only one of the ovules will develop into a seed. A single, massive obturator may cover the micropyles of both ovules, or each ovule may have its own thin obturator.
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Consequently, it reduces male fitness because geitonogamous pollen grains are barred from fertilizing ovules.
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Particularly, males and hermaphrodites have to have the same fitness, in other words the same number of offspring, in order to be maintained. However, males only have offspring by fertilizing eggs or ovules of hermaphrodites, while hermaphrodites have offspring both through fertilizing eggs or ovules of other hermaphrodites and their own ovules. This means that all else being equal, males have to fertilize twice as many eggs or ovules as hermaphrodites to make up for the lack of female reproduction. Androdioecy can evolve either from dioecious ancestors through the invasion of hermaphrodites or from hermaphroditic ancestors through the invasion of males.
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They have inferior ovary with 3 to 5 locules and each locule contains 2 ovules.
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According to this theory, loss of one of the LFY paralog led to flowers that were more male, with the ovules being expressed ectopically. These ovules initially performed the function of attracting pollinators, but sometime later, may have been integrated into the core flower.
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Anthers dorsifixed. - Stigma with lanceolate or linear lobes. Ovary multilocular. - Ovules basal, erect, 1 per locule.
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Moresnetiaceae were shrubs to trees with radiospermic ovules with a lagenostome and aggregated into multiovular cupules.
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Raphe, the adherent funiculus connecting the hilum and chalaza in anatropous or amphitropous ovules or seeds.
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The stigmas are elongated, appearing as false styles, known as stylodia. The ovary is located inside the flower, rather than below. It has two or three locules, with two ovules per locule. The ovules are attached to the partition that separates the locules, near its summit.
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A placenta runs along each side of the suture and bears 1 to 3 rows of numerous, tiny ovules. The ovules have been described as having one integument or two. The ovary hardly enlarges after anthesis. The fruit consists of 4 follicles joined at the base.
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Cast of Trigonocarpus trilocularis ovule showing stalk attachment; Massillon Sandstone (Upper Carboniferous), NE Ohio. Cast of a Trigonocarpus ovule showing one of the three longitudinal ribs. Ovules in different medullosalean species could vary from maybe 1 cm to over 10 cm long - the latter being the largest known ovules produced by any non-angiosperm seed-plant. It was traditionally believed that the ovules were borne directly on the fronds, replacing one of the pinnules on the ultimate pinnae.
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What they have in common is seeds with little or no endosperm . The ovules are often atropic.
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The two or three ovaries each contain two to five ovules. There are forty eight chromosomes (2n=48).
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These earliest ovules had the apical part of the nucellus exposed, from which there was a projection known as a lagenostome (sometimes also called a salpinx) that facilitated capture of the pollen and directed it down to the pollen chamber above the megagametophyte. In later, Pennsylvanian-age ovules such as Lagenostoma the nucellus became almost entirely encased by and fused to the integument, leaving just the small distal opening in the integument known as the micropyle through which pollen passed. Nevertheless, most lyginopteridalean ovules retained a lagenostome, despite its function in pollen capture having been replaced by the micropyle. As with all seed-plants, the lyginopteridalean ovules had just one functional seed megaspore within the nucellus.
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The gynoecium develops in an unusual way, similar to Winteraceae, with laminal placentation, i.e., the young carpel is cup-shaped, and the ovules develop on its upper surface. The margins of the carpel never fully fuse. A cleft remains filled with hairs, through which the pollen tubes grow towards the ovules.
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The female cones are open, very wooly and brown tomentose, with ovules per cone. Cones wide. Sarcotesta orange-brown.
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Ovary usually has two ovules per locule. One genus and over 500 species. Distributed over all the Northern hemisphere.
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Megasporangia are formed into ovules, which are borne on megasporophylls, which are aggregated into strobili on separate plants (all cycads are dioecious). Conifers typically bear their microsporangia on microsporophylls aggregated into papery pollen strobili, and the ovules, are located on modified stem axes forming compound ovuliferous cone scales. Flowering plants contain microsporangia in the anthers of stamens (typically four microsporangia per anther) and megasporangia inside ovules inside ovaries. In all seed plants, spores are produced by meiosis and develop into gametophytes while still inside the sporangium.
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"united bottle-shaped") and symplicate zones are fertile and bear the ovules. Each of the first three families possess mainly bi- or multilocular ovaries in a gynoecium with a long synascidiate, but very short symplicate zone, where the ovules are inserted at their transition, the so-called cross-zone (or "Querzone"). In gynoecia of the Pittosporaceae, the symplicate is much longer than the synascidiate zone, and the ovules are arranged along the first. Members of the latter family consequently have unilocular ovaries with a single cavity between adjacent carpels.
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There are 13–37 ovules per ovary, and the capsule is 6.5–12 mm long. It flowers from December to April.
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The expansin domain II, causative of the allergenic effects, could be related to the competition between pollens for access to ovules.
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The woody nature of associated stalks and preserved short shoots are evidence that Caytoniales were seasonally deciduous, shrubs and trees. Caytoniales had fertile branches with seed- bearing cupules . The ovules were located inside fleshy cupules with tough outer cuticle. Individual ovules had an apical tube called a micropylar canal, that allowed pollen to pass into the pollen chamber.
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The ovules are approximately 50 in each carpel, one of the structural units of a pistil, representing a modified, ovule-bearing leaf.
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It has numerous stamens that are 1.5 millimeters long. Its flowers have up to 10 carpels. Its carpels have 16-20 ovules.
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Ovary usually has two ovules per locule, side by side. Floral symmetry zygomorphic, septal nectaries absent. Nine genera native to South America.
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Such mechanisms include dispersal of pollen in aggregated packets and closure of the stigmatic lobes after pollen is introduced. The aggregated pollen packet releases pollen gametes in the ovary, thereby increasing likelihood that all ovules are fertilized by pollen from the same parent. Likewise, the closure of the ovary pore prevents entry of new pollen. Other multi-ovulated plants have evolved mechanisms that mimic the evolutionary adaption of single-ovulated ovaries; the ovules are fertilized by pollen from different individuals, but the mother ovary then selectively aborts fertilized ovules, either at the zygotic or embryonic stage.
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Pollen is contained in sacs of two to four at the tips of sporophylls on the strobiloid. Ovules of Ginkgo trees come from stalks from leaf axils on the short shoots, each containing two ovules. The ovule is fertilized by the flagellated male gametes, which can move about freely. This fertilization process begins on the tree itself in the spring.
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Wats.) Kurl.Species:Kurl. Boguslav Stanislavovich Kurlovich in new combination Subgen. PLATYCARPOS (S.Wats.) Kurl. and Subgen. LUPINUS integrates the numerous perennial and annual species from the Western hemisphere, both groups having two and more ovules or seedbuds in the ovary, while subgen. Lupinus L. includes 12 species from the Mediterranean region and Africa with at least four ovules or seedbuds in the ovary. Subgen.
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The funiculus abscisses (detaches at fixed point – abscission zone), the scar forming an oval depression, the hilum. Anatropous ovules have a portion of the funiculus that is adnate (fused to the seed coat), and which forms a longitudinal ridge, or raphe, just above the hilum. In bitegmic ovules (e.g. Gossypium described here) both inner and outer integuments contribute to the seed coat formation.
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Each stamen has two divergent, oblong and curved thecae. The two-locular ovary has numerous ovules, and produces numerous seeds in a fruit capsule.
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Gerrardina, Dipentodon, and Perrottetia have two ovules in each locule. Tapiscia lacks the nectary disk that is characteristic of the order. Huertea lacks stipules.
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However, it is technically difficult to isolate the tiny intact embryos, so often ovaries with young embryos, or entire fertilized ovules will be used.
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Each ovary contains numerous ovules. Its flowers have 3 styles that are 6 millimeters long and fused at their base for the last 1 millimeters.
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Ovary usually has two, four or numerous ovules per locule in two longitudinal rows. One genus and over 500 species. Distributed over all the Northern hemisphere.
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Its stamens are 1 millimeter long. Each flower has as many as 12 carpels that are 1 millimeter long and hairy. Each carpel has about 4 ovules.
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Each carpel contains 1 (-2) anatropous ovules. Fruit is a head of nutlets (except in Damasonium). The seeds have no endosperm and a curved or folded embryo.
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At the end of the growing season, mature fruits were harvested, and the number of mature seeds and unfertilized ovules was counted on exclosure and control individuals.
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He recorded foreign pollen in the ovules of living Ginkgo biloba and noted in the New Phytologist (1915), the problem with assuming that fossil pollen in ovules belonged to a single species. Sahni was among the first to suggest a separate order, the Taxales, within the conifers to contain the genera Taxus, Torreya and Cephalotaxus.Gupta (1978):34. Another major contribution was in the studies on the morphology of the Zygopteridaceae.
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There are usually twice as many stamens as petals, arranged in two whorls, and the stamens are often unequal in length. Occasionally, the stamens are reduced to one whorl, or are more numerous with multiple whorls. The ovary is typically superior, infrequently semi-inferior, or rarely inferior. The two to many carpels can be fused together (syncarpous), with two to numerous ovules in each locule, with axile placentation of the ovules.
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The maintenance of gynodioecy at first may seem like a mystery. Theoretically, hermaphrodites should have the evolutionary and reproductive advantage over females in a population because they naturally can produce more offspring. Hermaphrodites can transmit their genes through both pollen and ovules, whereas females can only transmit genes via ovules. Thus, in order for females to remain viable in a population, they would have to be twice as successful as hermaphrodites.
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Their flowers have hairless carpels with oblong ovaries. Within the ovaries the numerous ovules are positioned axially in two rows. Its elongaged styles are grooved on the inside.
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It has a stigmoid apex 0.1 mm (0.004-inch) to 0.2 mm (0.008-inch) by to 0.4 mm (0.016-inch). The ovules are approximately 50 in each carpel.
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Ovary incompletely 4-locular. Ovules 4. Style terminal on the ovary, bifid. Fruit a drupe, usually with 4 grooves or lobes, 4-seeded (rarely 2-seeded by abortion).
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Ovaries 2 to 5 with several ovules in two rows. Stigma discoid, sessile. Carpels thick-walled, sessile or sub-sessile. Meiogyne is different from Cyathocalyx in several ways.
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168x168px 211x211px Developed seed of C. micronesica. Image from Thomas Marler. Cycads, being gymnosperms, are dioecious organisms. Females possess clusters of ovules situated on modified leaves called megasporophylls.
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Such reduction can be assumed to be caused by the offspring: If the maternal parent's interest were to produce as few seeds as observed, selection would not favour the production of extra ovules that do not mature into seeds. (Although other explanations for this phenomenon exist, such as genetic load, resource depletion or maternal regulation of offspring quality, they could not be supported by experiments.) There are several possibilities how the offspring can affect paternal resource allocation to brood members. Evidence exists for siblicide by dominant embryos: Embryos formed early kill the remaining embryos through an aborting chemical. In oaks, early fertilized ovules prevent the fertilization of other ovules by inhibiting the pollen tube entry into the embryo sac.
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The succulent, tangy flesh is white, yellow or orange and sweet to subacid or acid, depending on the cultivar. Each fruit contains from one to ten ovules, with three to five being most common. A variable number of the ovules mature into large brown seeds (with different numbers of seeds appearing in each fruit on the same tree, usually between one and four). The fruits are the sweetest when soft and orange.
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Grains of pollen sticking to this bee will be transferred to the next flower it visits The primary purpose of a flower is reproduction. Since the flowers are the reproductive organs of plant, they mediate the joining of the sperm, contained within pollen, to the ovules — contained in the ovary. Pollination is the movement of pollen from the anthers to the stigma. The joining of the sperm to the ovules is called fertilization.
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The genus Lupinus L. and, in particular, its North American species were divided by Sereno Watson (1873) into three sections: Lupinus, Platycarpos, and Lupinnelus. Differences in habitat and in the number of ovules were the basis for this classification. A majority of the perennial and annual species from the American continent described by Watson were referred to Lupinus. Some annual species with two ovules in the ovary and two seeds in the pod (L.
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Two more groups of genes, D to form ovules and E for the floral whorls, complete the model. The genes are evidently ancient, as old as the flowering plants themselves.
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The receptacles of the flowers are hairy. Its flowers have 24 carpels that are covered in fine downy hairs. Its styles are hairless. Its ovaries have variable numbers of ovules.
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Individual flowers have six white to pale green or yellow tepals. The ovary has three locules with two ovules per locule. The fruit is a berry with a few brown seeds.
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Stamens 3 to 100. Ovary superior. Carpels 3 to 20, in 1 (rarely 2) whorls, free or basally connate. Ovules 12 to 100 per carpel and scattered over the inner surface.
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Lagenostoma has large (7–8 mm) ovules arranged in branching structures. The genus name comes from the distinctive prepollen receiving structure of a cone blocked by a growing plug of tissue.
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The stamen is 8–15 mm long, and can be acute or bifid at the apex. Lastly, the A. Pubescens have four ovules, which enables them produce maximum amount of seeds.
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It is worth noting that on their plate for Gumillea, Ruiz and Pavón showed 11 ovules or immature seeds that had been extracted from a 2-locular ovary. But the ovary in Picramnia has (sometimes 2), usually 3 to 4 locules and there are always two ovules in each locule. It might be possible to determine the affinities of Gumillea if DNA could be extracted from the existing specimen. DNA has been successfully amplified from specimens of similar age.
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A carpel is a modified megasporophyll consisting of two or more ovules, which develop conduplicatively (folded along the line). The carpels may be single, or collected together, to form an ovary, and contain the ovules. Another term, pistil, refers to the ovary as its expanded base, the style, a column arising from the ovary, and an expanded tip, the stigma. Within the stamen, the microsporangium forms grains of pollen, surrounded by a protective microspore, which form the male gametophyte.
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Calyx small with 4 minute, acute sepals. Petals 4, obovate-oblong. Stamens 8, free; anthers ovoid. Ovary seated on an annular disk, 2-locular; each locule with 2-collateral ovules; stigma subcapitate.
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The chalaza (; from Greek "hailstone"; plural chalazas or chalazae, ) is a structure inside bird and reptile eggs and plant ovules. It attaches or suspends the yolk or nucellus within the larger structure.
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The ovary consists of three united carpels with two ovules per carpel. The ovary is 1-loculate, but partly 3-loculate at its base. The fruit is a 1-seeded drupaceous capsule.
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The locules contain the ovules or seeds. The term may also refer to chambers within anthers containing pollen. In Ascomycete fungi, locules are chambers within the hymenium in which the perithecia develop.
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Anthers latrorse, at least in bud, opening by longitudinal slits, or in Poranthera, by pores. Ovary usually divided into three locules. Two ovules in each locule. Styles free to almost completely fused.
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Lyginopteridaceae were shrubs and vines with radiospermic ovules containing a lagenostome. They consisted of forms with monostelic stem petioles usually with single strand and small seeds. Family members include Lyginopteris and Heterangium.
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The usual color is white with crimson veins, but pink or purple also occur naturally. Stamens are very shortly connate basally, declinate, unequal. Style is declinate, stigma is three-lobed. Ovules are approx.
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Their flowers have numerous stamen. Their flowers have 3-5 carpels with ovules in two ventral rows. Their seeds are brown, oval and are rounded on one side, but angular on the other.
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Most medullosalean ovules preserved as casts or adpressions show three longitudinal ribs and are assigned to the fossil genus Trigonocarpus. When such ovules are preserved as petrifactions, they are assigned to the fossil genera Pachytesta or Stephanospermum, depending mainly on differences in the apical form of the ovule. Another group of medullosalean seeds, usually associated with parispermacean fronds (see later), have six longitudinal ribs and are referred to as Hexagonocarpus when found as adpressions or casts, and Hexapterospermum when found as petrifactions.
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The genus Lupinus L. and, in particular, its North-American species, were divided by Sereno Watson (1873) into three parts: Lupinus, Platycarpos and Lupinnelus. Differences in habit and in the number of ovules were accepted as the basis for this classification. A majority of perennial and annual species from the American continent described by Watson were referred to Lupinus. To the Platycarpos section were attributed some annual species with two ovules in the ovary and two seeds in the pod (L.
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May contain from one to several ovules in each locule. They have nectaries at the septa of the ovaries. Fruit: dehiscence loculicidal. Seed: Seed morphology is diverse, from globular to flattened, and occasionally aril.
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Ovary usually has two ovules per locule, side by side. Floral symmetry actinomorphic, septal nectaries present. Six genera and 42 species, and endemic to South America with the exception of two species of Nothoscordum.
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The stigmas have two lobes. The carpels have numerous ovules. The fruit can be round, ellipsoidal or oblong and either hairless or covered in fine downy hairs. The fruit can be smooth or ribbed.
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Its ovules are arranged in to rows positioned ventrally in ovaries. Its fruit have numerous seeds in a single row. The brown seeds are oval, rounded on one side and angled on the other.
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The female flowers have 2 to 6 stigmas. They have a 1-locular ovary with 2 ovules. The globose to ellipsoid fruits resemble a drupe. Their color varies from green to white, red and black.
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Its stigmas are bilobed. The carpels contain numerous ovules in two rows. Its are green to yellow with white spots, 6-10 by 4-6 centimeters, and have a contour that is constricted around the seeds.
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The flowers are pink to purple, with five stamens inserted into the tube. Ovaries have numerous ovules. Flowering season is April through June. The fruits mature in August through September, with some coming out of season.
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However, when these flowers are retained on insect pollinated plants there are the potential benefits of enhanced reproductive success through increased pollen deposition on stigmas and export of pollen to fertilize the ovules of other plants.
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Subgenus Lupinus consists of 12 species from Africa and the Mediterranean, with a minimum of four ovules or seedbuds.Kurlovich, B. S. and A. K. Stankevich. (eds.) Classification of Lupins. In: Lupins: Geography, Classification, Genetic Resources and Breeding.
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Flowers are pentamerous, white and solitary in auxiliary spikes. M. glauca is usually hermaphroditic or sometimes unisexual by abortion of pollen or ovules. The corolla tube is short with spreading lobes. Flowering occurs in January and February.
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Ovary usually has two ovules per locule, side by side. There are 2–3 stamens. The commonest chromosome number is x=4. Gilliesiae is distinguished from Leucocoryneae by zygomorphic floral symmetry and the absence of septal nectaries.
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Like other members of the Mimosoideae subfamily, Parkia pendula exhibits pollen aggregation, specifically polyads. It further differentiates itself from other members of Mimosoideae by having globose polyads rather than flattened polyads from pollen grain layering. Parkia pendula polyads are about 100 mm in diameter and composed of 32 pollen grains, with an outer exine that is grooved. The stigma for each fertile flower only contains a cavity for one polyad, but since the number of pollen grains matches the number of ovules, one polyad can fertilize all the ovules of a flower.
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The swollen fruit-like ovules, about 2–3 cm in diameter, fall from the tree in the fall, and fertilization continues into the winter/spring. This fruit contains a single large seed, similar to that of a cycad.
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Ovules usually 2 per locule; sometimes 4, rarely many. Nectary disk, when present, encircling the base of the ovary. The plants are most often hermaphrodite but sometimes polygamomonoecious. The fruit can be a berry, drupe, capsule or samaras.
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Lab-on-a-chip devices could be used to characterize pollen tube guidance in Arabidopsis thaliana. Specifically, plant on a chip is a miniaturized device in which pollen tissues and ovules could be incubated for plant sciences studies.
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The carpels have 1-2 ovules. Its hairless styles are 3 millimeters long with thickened tops. Its stigma have two lobes. Its oblong to oval, wrinkled, hairless fruit are 2 centimeters long with rounded tips and pointed bases.
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Its flowers have 10-22 green, oblong, densely hairy carpels that are 2-2.5 millimeters long. Its carpels have around 10 ovules. Its fruit are 2-4 by 0.8-1 centimeters and covered in dense, brown, velvety hairs.
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Its oval ovaries are 3-4 x 2-2.5 millimeters with two compartments. Each compartment has more than 50 ovules. Its hard, elliptical to oval, yellow fruit are 6.5-20 by 6-13.5 centimeters with pointed or rounded tips.
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Rothwell, G. W. (1980). "The Callistophytaceae (Pteridospermopsida): II Reproductive features." Palaeontographica, Abteilung B, 173: 85-106. The ovules were borne on the underside of pinnules that did not differ significantly in form from those of the purely vegetative fronds.
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The leaf veins of Huberantha form an interconnected net-like pattern. Their flowers are axillary. They have a single ovule and seed per ovary. A portion of their ovules remain fused to the seed coat forming a flat raphe.
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The petiole is brown pubescent, 25–35 cm long, armed with spines. The female cones open, with sporophylls 15–20 cm long, grey with orange hairs, each with 4-6 ovules. Margins toothed, with bright orange sarcotesta when ripened.
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The inner petals are 15 by 15 millimeters. Its anthers are 2 millimeters long. Its flowers have many carpels, each with 4-6 ovules. Its large fruit consists of up to 40 oval, brown, wrinkled carpels on short stalks.
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This plant is usually distinguished by its few, erect, rough textured leaves. Each flower usually contains 6 stamens with the inner stamens usually reduced. This species has short filaments and stigmas. There are 3 ovaries each with 2 ovules.
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The ovary has five locules and is more or less spherical with five shallow lobes and there are between four and six ovules in each locule. The fruit is a woody capsule splitting into five and contains brown, winged seeds.
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This subfamily is defined as those species having cluster roots, solitary ovules and indehiscent fruits. Proteoideae is further divided into four tribes: Conospermeae, Petrophileae, Proteae and Leucadendreae. The genus Protea, and hence P. cynaroides, is placed under the tribe Proteae.
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This is a genus of evergreen, robust, climbing plants. The flowers are bisexual, lacking a perigone. The spathe is shed after flowering. The ovules number eight or more and are superposed on two (rarely 3) parietal placentas of the ovary.
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The ground color of the hindwings is white, with a narrow blackish area around the apex. The larvae feed on Cryptantha intermedia. They feed inside the buds of their host plant. First instar larvae feed at the sides of developing ovules.
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The anthers are yellow, erect, and subglobular. The five staminodes are opposite the petals and dilated at the ends. The gynoecium is unilocular and composed of three fused carpels. The ovules are numerous and attached near the margins of the carpels.
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The northern jacana feeds on insects on the surface of vegetation and ovules of water lilies. It also consumes snails, worms, small crabs, fish, mollusks, and seeds. The jacana competes with birds of a similar diet like the sora.Stephens, M.L. (1984).
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In particular, the energy cost of producing ovules and fruit in female plants is greater than the cost of male flowers producing pollen. Female-biased sex ratios also occur as a consequence of differential fertilization and genetic differentiation of sex chromosomes.
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Flowering occurs in early spring with seed production occurring by early July. The plant forms tiny perfect flowers clustered in a cylindrical spike. Each flower/pod has five stamen, two ovules per pod, and only one seed matures per pod.
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Pollen-producing cones fusiform (tapering at both ends), microsporophylls (male, pollen-producing) up to 45 mm long. Megasporophylls (female, ovule-producing) up to 30 cm long, each with 2-5 ovules. Seeds flattened to ovoid, orange-brown.Lindstrom, AJ, & KD Hill. 2002.
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The anthers are dorsifixed. The three-loculed ovary have many ovules per locule. The styles are arranged into a column. The three- angled fruits are broadly cylindrical capsules and when ripe release many small, flat, ovate to orbicular shaped seeds.
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Placentation is axial, rarely parietal (e.g. Gardenia); ovules are anatropous to hemitropous, unitegmic, with a funicular obturator, one to many per carpel. Nectaries are often present as a nectariferous disk atop the ovary. The fruit is a berry, capsule (e.g.
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The cones and seeds of Sciadopitys (the only member of the family) are similar to those of some Cupressaceae, but larger, 6–11 cm long; the scales are imbricate and spirally arranged, and have 5-9 ovules on each scale.
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As such, the reproductive traits and behaviors of plants suggests the evolution of behaviors and characteristics that increase the genetic relatedness of fertilized eggs in the plant ovary, thereby fostering kin selection and cooperation among the seeds as they develop. These traits differ among plant species. Some species have evolved to have fewer ovules per ovary, commonly one ovule per ovary, thereby decreasing the chance of developing multiple, differently fathered seeds within the same ovary. Multi-ovulated plants have developed mechanisms that increase the chances of all ovules within the ovary being fathered by the same parent.
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The gymnosperms are a group of seed producing plants that includes conifers, Cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilised state). Their naked condition stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, often modified to form cones, or at the end of short stalks as in Ginkgo.
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Pistils begin as small primordia on a floral apical meristem, forming later than, and closer to the (floral) apex than sepal, petal and stamen primordia. Morphological and molecular studies of pistil ontogeny reveal that carpels are most likely homologous to leaves. A carpel has a similar function to a megasporophyll, but typically includes a stigma, and is fused, with ovules enclosed in the enlarged lower portion, the ovary. In some basal angiosperm lineages, Degeneriaceae and Winteraceae, a carpel begins as a shallow cup where the ovules develop with laminar placentation, on the upper surface of the carpel.
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In the latter case, separate terms are used depending on whether or not the ovary is divided into separate locules. If the ovary is divided, with the ovules born on a line of placentation at the inner angle of each locule, this is axile placentation. An ovary with free central placentation, on the other hand, consists of a single compartment without septae and the ovules are attached to a central column that arises directly from the floral apex (axis). In some cases a single ovule is attached to the bottom or top of the locule (basal or apical placentation, respectively).
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A major difference between vascular and non-vascular plants is that in the latter the haploid gametophyte is the more visible and longer- lived stage. In vascular plants, the diploid sporophyte has evolved as the dominant and visible phase of the life cycle. In seed plants and some other groups of vascular plants the gametophyte phases are strongly reduced in size and contained within the pollen and ovules. The female gametophyte is entirely contained within the sporophyte's tissues, while the male gametophyte in its pollen grain is released and transferred by wind or animal vectors to fertilize the ovules.
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Stamens are reflexed in anthesis and have basal and apical sterile appendages. Many species also exhibit secondary pollen presentation. The 5-locular ovary contains two ovules per locule. The drupaceous fruits contain pyrenes with one seed due to the abortion of one ovule.
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The Board of Trustees of the Royal Botanic Gardens, Kew. The genus is closely related to Typhonium. The only apparent difference between the two is in how many ovules each have and the overall size of the plants. Typhoniums are bigger than Theriophonum.
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Its flowers have numerous stamens that are 5 millimeters long. Each flower has a 4-chambered ovary. Each ovary contains numerous ovules. Its flowers have 4 curved styles that are 7.5 millimeters long, and fused at their base for the last 2 millimeters.
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A current schema retains this distinction, but uses the nomenclature for the subgenera of Platycarpos and Lupinus. In this schema, subgenus Platycarpos (S.Wats.) Kurl. contains perennial and annual species from the Western Hemisphere, with a minimum two or more ovules or seedbuds.
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The flower has a syncarpous gynoecium (fused-carpellate ovary) with 5 carpels and has parietal placentation. Ovules are numerous and small. The small fruit is spherical and dehiscent. Its appearance is red when immature and black/brown when mature, with a glabrous surface.
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While the female spike length of about 3–6 cm, with bracts long ovary stalk, spindle-shaped ovary which has 6-10 ovules, short style on the split 4 petals into a cross, ovary at the bottom of only one gland body.
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The ovary is superior, usually surrounded by a nectary disk, composed of two carpels, bilocular and with a septum, except unilocular in Tourrettia and quadrilocular in Eccremocarpus. Placentation is axile, except parietal in Tourrettia. Ovules are numerous. Bignoniaceae flower, upper lip removed.
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Leaflets in 85-155 pairs, and lanceolate, glabrous and angled forward at 60-70 degrees. Female cones closed type, sporophylls 13–18 cm long with yellow to gray tomentose. 2-4 ovules per sporophyll. Lamina is long, almost circular, with numerous lateral spines.
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6 - 9 stamens. Carpels superior, 6 - 9 and slightly united at the base. When ripe they are obovoid and crowned with a persistent style. Ovules are numerous and found scattered over the inner surface of the carpel wall, except on the midrib and edges.
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The calyx tube is 1–2 mm long and has narrowly elliptic lobes. The corolla is yellow to yellow-orange. Ovules 3–5. The pod becomes dark grey with age, and is constricted between the seeds, and densely covered with colleters and minute hooked hairs.
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Corolla with a slender tube; lobes 5, spreading . Stamens 4, ovary 4-locular; ovules pendulous or laterally attached. Style with 2 acute stigmatic lobes. Fruit is a drupe with 4 1-seeded pyrenes, sometimes separating into 2 2-loculed or 4 1-locular mericarps.
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This cycle is known as alternation of generations. The spores of seed plants are produced internally, and the megaspores (formed within the ovules) and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and pollen grains.
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Trillium grandiflorum has long been thought to self- pollinate based on the fact that pollinators had rarely been observed visiting the plants and because there is low variation in chromosomal banding patterns. This has been strongly challenged, as other studies have shown high pollination rates by bumblebees and very low success of self-pollination in controlled experiments, implying that they are in fact self-incompatible. Several ovules of a given individual often fail to produce seeds. One contributing factor is pollen limitation, and one study showed that open pollinated plants had 56% of their ovules produce seeds, while in hand pollinated individuals the figure was 66%.
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The species exhibit a character that is not common in the family Rubiaceae, viz. the presence of two collateral and pendulous ovules per locule. The shrubs or trees have apical buds with abundant resin. Each flower is subtended by a bracteole and the corollas are contorted.
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Each carpel is deeply lobed, giving the impression that there are in fact 4 carpels, ostensibly isomerous with the perianth. The ovary is syncarpous and have either 4 or 2 locules, each one housing 1 or 2 anatropous ovules. Stigmas are inconspicuous. The placentation mode is basal.
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The walls of the carpels are incomplete so that the ovary is unilocular in its upper part. The placentation is parietal. The ovules are attached to T-shaped placentas in Parnassia, and directly to the ovary wall in Lepuropetalon. The style is absent or very short.
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The ovary is 3-sided and 3-locular, with 8 to 14 ovules per locule. The placentation is axile. The style is short and stout, surmounted by three small, triangular stigmas, these located opposite the stamens. The fruit is distinctive, easily attracting attention by its odd appearance.
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Pistils are depressed globose or depressed trapezoidal in shape, 1-locular and with many ovules. Stamens consist of short filaments with thecae at the tip, dehiscing by a pore. Pollens squeezed out from the theca pore like a droplet. Fruits are berries with round to ellipsoidal shapes.
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Ovules 1 per carpel Flowering season in India are from the month of December to May. Fruit: Fruits green to greenish brown, papery in texture. Samaras about 5-6 x 1–2 cm. Main vascular bundle to the seed connected to an intramarginal vein on the samara.
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However, unlike these other groups, ovules are produced on cone scales, which are modified shoots rather than sporophylls. Some plants do not produce sporophylls. Sporangia are produced directly on stems. Psilotum has been interpreted as producing sporangia (fused in a synangium) on the terminus of a stem.
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127 The raceme is 2–6 cm long. The fruit is a 3-celled capsule with two ovules in each cell. It is a very well known species in cultivation (being described as the "common" Grape Hyacinth by Mathew); it increases rapidly and can become invasive.
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The pistil is ovary superior, ovoid, and five-celled; the style is columnar; the stigma is simple; the disk is ten-toothed, and ovules are many. The fruit is a capsule, downy, five-valved, five-angled, and tipped by the persistent style; the pedicels are curving.
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The leaf petioles are 15–90 cm long, and armed with sharp spines at the base. The female cones are open, with sporophylls 13–25 cm long, with two to six ovules per sporophyll. The lamina is lanceolate, with spined dentate margins and an apical spine.
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Transactions of the Royal Society of Edinburgh, 66: 111-128.Long, A. G. (1966). "Some Lower Carboniferous fructifications from Berwickshire, together with a theoretical account of the evolution of ovules, cupules and carpels." Transactions of the Royal Society of Edinburgh, 66: 345-375.Long, A. G. (1969).
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Stamens 4–6, not opposite petals. The ovary has a single locule. Style is terete and only slightly inserted into the ovary summit. The unilocular ovary, where the pendulous placenta and ovules are enclosed by a single membrane, is characteristic to the species and unique in the genus.
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Petals oblong to sub-orbicular, with the margins entire ciliated or undulate. Disc deeply 5-lobed, sometimes 5-sided, collar-like or saucer- shaped, with crenate or undulate margins. Ovary 2-4-chambered, with 2 ovules in each chamber; style usually short; stigma 2-4-lobed. Fruit a capsule.
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On the other hand, a reciprocal cross (SI x SC) will not produce offspring, because the pollen tubes will not reach the ovules. This is known as unilateral incompatibility, which also occurs when two SC or two SI species are crossed.Hadley , H.H. & Openshaw, S.J. 1980. Interspecific and intergeneric hybridization.
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Flora of China Vol. 23 Page 10, 雷公连属 lei gong lian shu, Amydrium Schott, Annales Museum Botanicum Lugduno-Batavi 1: 127. 1863. Amydrium is distinguished from other members of the tribe Monstereae by having two ovules in each ovary. The seeds tend to be heart shaped.
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Pollen tubes act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. Pollen grains have separate structures such as microsporocytes and megasporocytes.
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There are usually nine stamens. The five ovaries do not develop seeds. Female flowers have rudimentary staminodes, and five to nine compressed ovaries, with a papillose exterior. The carpels each contain up to seven or eight ovules, of which usually one or two develop into pale brown, shiny seeds.
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In: Reuther, W. Webber, H. J., Batchelor, L. D. (eds) The Citrus Industry, vol. II: 290-324 University of California Press, Berkeley, California.Gmitter, F. G., Jr., Ling, X. (1991) Embryogenesis in vitro and nonchimeric tetraploid plant recovery from undeveloped Citrus ovules treated with colchicine. J. Amer. Soc. Hort.
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The emerging young leaves are white tomentose, soon becoming glabrous. The petioles are spiny and glabrous. The female cones are closed type, the sporophylls 8–12 cm long, dense brown tomentose, with two to four glabrous ovules, and soft lateral spines on the lamina, with no apical spine.
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Peltaspermaceae have umbrella-like (peltate) cupules with numerous pendant ovules born in complex large branching structures (Peltaspermum). The pollen organ (Antevsia) has radiating cigar- shaped pollen sacs attached to small blades, again in complex branching structures. The leaves (Lepidopteris) are bipinnate to tripinnate with small pinnules on the rachis.
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It has been observed that in sea urchins of the genus Strongylocentrotus the concentration of spermatocytes that allow 100% fertilization of the ovules of the same species is only able to fertilize 1.5% of the ovules of other species. This inability to produce hybrid offspring, despite the fact that the gametes are found at the same time and in the same place, is due to a phenomenon known as gamete incompatibility, which is often found between marine invertebrates, and whose physiological causes are not fully understood. In some Drosophila crosses, the swelling of the female's vagina has been noted following insemination. This has the effect of consequently preventing the fertilization of the ovule by sperm of a different species.
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Such a change in circumscription could result in an expansion of the range of plant parts and/or preservation states that can be incorporated within the taxon. For instance, a fossil-genus originally based on compressions of ovules could be used to include the multi- ovulate cupules within which the ovules were originally borne. A complication can arise if, in this case, there was an already named fossil-genus for these cupules. If palaeobotanists were confident that the type of the ovule fossil- genus and of the cupule fossil-genus could be included in the same genus, then the two names would compete as to being the correct one for the newly emended genus.
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Consider the evolution of the C-region gene AGAMOUS (AG). It is expressed in today's flowers in the stamens, and the carpel, which are reproductive organs. It's ancestor in gymnosperms also has the same expression pattern. Here, it is expressed in the strobili, an organ that produces pollens or ovules.
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They can be hairy with dark red, gland-tipped and tubercle-based hairs. The sepals are 2–3 mm long and persist with the fruit. The deep lilac-pink petals are 4.5–10.5 mm long and also persist in the fruitin. The ovary is hairy and there are two ovules.
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Spathe up to 15 mm long, caducous. Inflorescence with 3-15 up to 8-cm long spikes with omnilateral flowers; 2(3) white tepals; 6 stamens; 3(4) carpels with 2 ovules each. Fruit about 10 x 7 mm. Seed about 7x4 mm in size, simple testa (van Bruggen 1985).
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The inner petals have sparse hairs on their outer surface and dense, brown, woolly hairs on their inner surface. Its flowers have stamen that are 0.8-1.1 by 0.3-0.6 millimeters. The carpels have 10-12 ovules. Its flowers have 15-17 carpels that are 1-1.5 by 0.3-0.5 millimeters.
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One of the fertile stamens is longer and yellow; the other two are shorter and grey in colour. The gynoecium (female organ) has three joined carpels. Aerial and subaerial branch flowers have five ovules per ovary; underground branch flowers have three. Seeds are ovoid; 2 mm long and 1.5 mm wide.
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"Some Lower Carboniferous pteridosperm cupules bearing ovules and microsporangia." Transactions of the Royal Society of Edinburgh, 70: 1-11. but by Pennsylvanian times there was normally just a single ovule per cupule. A number of cases have been found of cupules occurring in clusters at the ends of branching axes.
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Cryptic self-incompatibility (CSI) is the botanical expression that's used to describe a weakened self-incompatibility (SI) system. CSI is one expression of a mixed mating system in flowering plants. Both SI and CSI are traits that increase the frequency of fertilization of ovules by outcross pollen, as opposed to self-pollen.
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The stamen are arranged in a spiral. Its flowers have 10-12 carpels that are 1.5-1.7 by 0.5-0.6 millimeters. The carpels have 8-12 ovules. Its fruit occur in clusters of up to 8–12 on woody pedicels that are 25 by 4.5-6 millimeters and covered in sparse, fine hairs.
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Petals 4–5 mm long, usually 5 or sometimes 6, valvate, spreading, deciduous. Stamens usually 5 or sometimes 6, inserted on the margin of the inconspicuous nectary disk; anthers broad oblong; filaments very short. Gynoecium of 5 carpels, receptacle patelliform. Ovary superior, 5-locular, with numerous axile ovules, stigma sessile, 5-lobed.
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It requires open, well-lit, shallow water to grow in and regularly churned-up mud for its seeds to germinate. It is very variable in form according to the depth of the water it is growing in. Dwarf plants with aerial leaves occur growing sub- terrestrially on mud. The number of ovules vary.
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Once the male strobilus has matured the microsporangia are exposed at which point the pollen is released. The female megasporangiate is larger than the male. It contains bracts and megasporophylls, each of which contains two ovules, arranged in a spiral. These then develop a nucellus in which a mother cell is formed.
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They have one style and one stigma; the latter is simple or bilobate. Each locule has one to 50 ovules that are anatropous or hemianatropous with axillar placentation. The development of the embryo sack can be the same as for Polygonum or Allium species. The embryo sack’s nuclear poles become fused before fertilization.
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The flowers are borne in cymose clusters with a minimum of three flowers, though they can also be solitary on the ends of branchlets. Each flower has about four to nine petals, two locules, and one to four ovules. They have two stamens with very short filaments. The bracts are linear or ovate.
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The thecae open by one valve. The ovary is half-inferior and, as in the rest of the family, consists of two carpels. The number of ovules in each carpel has been reported as five or six and as six to eight. What some authors have loosely called styles are actually styluli.
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The long flowers styles tend to prevent wasps from laying their eggs within the ovules, while the short styled flowers are accessible for egg laying. All the native fig trees of the American continent are hermaphrodites, as well as species like Indian banyan (F. benghalensis), weeping fig (F. benjamina), Indian rubber plant (F.
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The flowering stem bears pyramidal raceme of a few flowers; each flower is blue, with six tepals, each 12 mm long and 2,5 mm wide. The flower has 4-7 ovules in each carpel. The flower's elaiosomes are pearl-like, and grouped to form a disc. It flowers from March to April.
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Corollae have five mostly unequal petals, and the anterior petal is larger and often spurred. Plants have five stamens with the abaxial stamen often spurred at the base. The gynoecium is a compound pistil of three united carpels with one locule. Styles are simple, with the ovary superior and containing many ovules.
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Cryptic self- incompatibility favors fertilization by outcrossing pollen, when both outcross and self-pollen are present on the same stigma. CSI promotes fertilization by outcross pollen due to faster growth rate of outcross pollen tubes. Reproduction assurance occurs when there is insufficient outcross pollen present to attain fertilization of all of the ovules.
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Up to 1000 ovules (potential kernels) form per ear of corn, each of which produces a strand of corn silk from its tip that eventually emerges from the end of the ear. The emergence of at least one strand of silk from a given ear of corn is defined as growth stage R1, and the emergence of silk in 50% of the plants in a corn field is called "mid-silk". The silk lengthens from the basal ovules during the 10 to 14 days previous to growth stage R1; this is due to a change of shape of existing cells rather than their replication. The elongation progresses at 1.5 inches per day at first, but gradually slows as the full length is approached.
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Callospermarion ovules from the Early Permian of northern China: palaeofloristic and palaeogeographic significance of callistophytalean seed–ferns in the Cathaysian flora. Review of Palaeobotany and Palynology 120: 301–314. vegetative foliage of Emplecopteris triagularis,Seyfullah, L. J. and Hilton, J. (2009). Re–evaluation of Halle’s fertile pteridosperms from the Permian floras of Shanxi Province, China.
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The waxy yellow colored inner petals are smooth on their upper and lower surfaces. Each inner petal has an ovoid gland at the base of its outer surface. Male flowers have up to 39 stamens that are 0.6-0.7 millimeters long. Female flowers have up to 7 carpels per flower and 3 ovules per carpel.
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P. driftwoodensis, in contrast, has a parenchymatous pith, seen in the modern Pinus subsections Australes, Ponderosae, and Sabinianae. The cone scales are high by with a rhomboidal shape and inflated dorsal umbo at the scale tip which do not show evidence of a spine. each scale bears two ovules in diameter on its upper surface.
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The petals overlap at the base and there are twice as many stamens as petals, usually alternating in length. There are usually five carpels in each ovary and two ovules in each locule. The fruit has up to five follicles joined at the base, each follicle with a single, smooth brown seed about long.
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Econazole is used as a cream to treat skin infections such as athlete's foot, tinea, pityriasis versicolor, ringworm, and jock itch. It is also sold in Canada under the brand name Ecostatin as vaginal ovules to treat vaginal thrush. Econazole nitrate exhibits strong anti-feeding properties against the keratin-digesting common clothes moth Tineola bisselliella.
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Normally pollen is moved from one plant to another, but many plants are able to self pollinate. The fertilized ovules produce seeds that are the next generation. Sexual reproduction produces genetically unique offspring, allowing for adaptation. Flowers have specific designs which encourages the transfer of pollen from one plant to another of the same species.
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Dipentodon and Perrottetia are distinctive in that the calyx and corolla are not well differentiated, but resemble each other. Tapiscia and Huertea have a calyx tube and compound, rather than simple leaves. Tapiscia has a uniloculate ovary with a single ovule. Huertea has one locule containing two ovules, or two locules, each containing one ovule.
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Severino Antinori (born 6 September 1945 in Civitella del Tronto) is an Italian gynecologist and embryologist. He has publicly taken controversial positions over in vitro fertilisation (IVF) and human cloning. On 13 May 2016 Antinori was arrested and accused of kidnapping a woman, and stealing her ovules. He began his career interested in veterinary biology.
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Trees up to 30 m tall, dark brown bark. Leaves elliptic to oblong, 3–29 cm long and 1.2–3 cm wide, apex acumiunate, base cuneate. Male cones axillary, sessile, solitary, up to 5 cm long. Ovules on a receptacle of 1.2 cm long, at the end of a 1–2 cm long peduncle.
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The sparsely pubescent calyx is 5–7 mm long. The standard and wing petals are mostly yellow or orange, while the keel is dark red and longer than the other petals by 8–10 mm. The ovary is glabrous and has about 8 ovules, while the pod is about 15-20 mm long and oblong.
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A characteristic feature of the stems is the presence in the cortex of spherical secretory structures. Similar structures have also been found in associated ovules, pollen-organs and foliage, and were one of the main lines of evidence on which the reconstruction of the plant was based (compare with similar evidence used to reconstruct the Lyginopteris- bearing fossil plant).
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Ginkgos are dioecious, with separate sexes, some trees being female and others being male. Male plants produce small pollen cones with sporophylls, each bearing two microsporangia spirally arranged around a central axis. Female plants do not produce cones. Two ovules are formed at the end of a stalk, and after pollination, one or both develop into seeds.
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The inner surface of inner petals is covered in glandular hairs that become longer at the tip and cause the petals to interlock to form a dome. Its flowers have stamen that are 0.4-0.7 by 0.4-0.6 millimeters. Its flowers have 9-10 carpels that are 0.9-1.4 by 0.4-0.5 millimeters. The carpels have 4-6 ovules.
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Spathe up to 1.5 cm long, caducous. Inflorescence with 2, seldom 3 up to 14 cm long spikes with omnilateral flowers; 2 white tepals; 6 stamens; 3-4 carpels with 2(-4) ovules each. Fruit about 6x3 mm in size, with a terminal beak. Seeds up to 3.25 x 1.5 mm in size, simple testa (van Bruggen, 1985).
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The flowers lack petals. The male flowers generally have 5-12 stamens with sepals that are cup-shaped. The female flowers lack a style, and have one locule, the compartment in the ovary that contains the ovules. The number of locules varies within different species in the genus; hence, this the best way to distinguish the medullosum species.
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Thesium humifusum usually grows flat along the ground, only occasionally producing more erect flowering stems. Its leaves are a yellowish green colour and are strap-shaped and up to long, with a single central vein. The flowers are also yellowish, and only long. They have five tepals, five stamens, and a single ovary with three ovules and one style.
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Cordaites, a tall plant (6 to over 30 meters) with strap-like leaves, was related to the cycads and conifers; the catkin-like reproductive organs, which bore ovules/seeds, is called Cardiocarpus. These plants were thought to live in swamps. True coniferous trees (Walchia, of the order Voltziales) appear later in the Carboniferous, and preferred higher drier ground.
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During the period of pregnancy, their clutch size may decrease due to a lack of fertilization. It was reported that during the mating period of vitellogenesis which means McCann's skinks mate in autumn season and discharge ovules in spring, male McCann's skinks’ sperms must be stored inside female's reproductive tract for several months to have reproductive success.
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The inner petals are smooth on their upper surface, densely hairy on their lower surface and have hairy margins. The inner surfaces of the inner petals have numerous distinctive glands. Male flowers have 100-143 stamens that are 0.6-1.1 millimeters long. Female flowers have up to 15 carpels per flower and 6-7 ovules per carpel.
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The cream-colored inner petals are smooth on their upper surface and densely hairy on their lower surface. Each inner petal has a crown-shaped gland at the base of its outer surface. Male flowers have up to 29 stamens that are 0.6 millimeters long. Female flowers have up to 7 carpels per flower and 2 ovules per carpel.
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Developing seeds are borne on axile or parietal placentae, with at least two ovules per placenta. Hypericum fruits are dissimilar to most of Hypericaceae, being capsular and dehisce from the apex. The capsule can be dry or remain fleshy when mature. The capsules have elongate or punctate glands on their surface that create various shapes and patterns.
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The flowers have five petals and sepals and numerous conspicuous stamens. Ovary is superior and has only one carpel with numerous ovules. Flowering is followed by the seed pods, which are ripe over November to January. Dark brown or reddish brown to black colour of the seed are located inside of parallel sided, flattish, smooth pod.
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The outer petals are covered in fine hairs. The oval inner petals are 5–14 by 3–8 millimeters with tapering tips. The outer petals are covered in fine hairs. Its flowers have few narrow, short ovaries, each with 1-2 ovules. Its long styles are thicker toward their apex. Its funnel-shaped stigma have a toothed edge.
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The ovary is unilocular, at least at the top, with one or two ovules per carpel. The number of carpels is variable. Other characters are generally found in Huerteales, but with the exceptions noted below. Gerrardina differs from the rest of Huerteales in that the stamens are opposite the petals, instead of being opposite the sepals.
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It is a plant of the dry mountainous scrub, where it grows on gritty limestone cliffs. July gold is a rare plant, and its populations are scattered due to its specific niche habitat. It is also a poor reproducer; only about 1% of its flower ovules produce viable seed. These factors make it a species of concern.
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When pollen competition occurs, the competitive ability is determined by differences between tube growth rate or the time it takes for germination to occur. Pollen completion is increased when pollen is not limiting and when pollen is in abundance relative to the number of ovules present in the ovary, but this does not guarantee pollen competition.
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Inflorescences are often in the form of a spike or raceme made up mostly of staminate flowers with some pistillate clusters around the base. Staminate flower heads have stamens surrounded by whitish or purplish florets. Pistillate flower heads have fruit-yielding ovules surrounded by many phyllaries and fewer, smaller florets. The pistillate flowers are wind pollinated,Genus Ambrosia.
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The petals and staminodes are usually yellow to red. The three carpels are at a constant under (syncarp) ovary adherent which has a soft-spiky surface and many central angle constant ovules contains. The pollen is deposited on the abaxial (off- axis) surface of the stylus. The pollination mechanism is very specialised and the pollination is done by insects.
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In the leaves, the MMP gene was expressed in the phloem, developing xylem elements, neighboring mesophyll cell layers, and epidermal cells. The flowers were noted as having the gene in pistils, ovules, and receptacles. It was concluded that the At2-MMP has a physiological role in mature aging tissue and the possibility of being involved in plant senescence.
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Its ovaries are 1.5-2.3 by 0.8-1.2 millimeters, covered in dense fine hairs, have a single chamber, convex backs, and flat faces. Each ovary has 7-8 ovules arranged in two rows. Its cone-shaped, broad stamens are 2.4 by 1.6 millimeters, concave on the back, and convex on their face. The stamen filaments are indistinct.
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The ovaries are superior and sessile with three (four in Beauverdia) carpels and locules (four in Beauverdia) and septal nectaries. The number of ovules is either 2, 4 or 30 per locule, arranged in two rows. The style is apical and persistent. The stigma has three (four in Beauverdia) lobes, or is trifid, and is papillose.
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Flowers of Argemone albiflora contain 3 long sepals and 6 petals and is ovate to almost circular with a rugged outer margin. The ovary is single chambered and contains many ovules with 3 to 5 lobed purple stigma. The fruit of this plant is a spiny capsule opening by the terminal splits. The seeds are brownish black.
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The inner petals have sparse, fine hairs on their outer surface. The inner surface of inner petals is covered in hairs that become longer at the tip. Its flowers have more than 100 yellow stamen that are 1.5-1.9 by 0.7-0.9 millimeters. Its flowers have 7-8 carpels that are 2-2.5 by 0.9 millimeters. The carpels have 8-10 ovules.
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Two large, ovate to elliptic bracteoles subtend and protect the young corolla. The persistent bracteoles may be conspicuously veined or covered by long, villous trichomes. The small, ellipsoid fruit capsules explosively release two to four flat seeds (two ovules per ovary cell) when moisture is absorbed by their hygroscopic hairs. Young foliage and branches are covered in gland-tipped hairs.
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The ovaries are superior, hairy, abortive in the staminate flowers, two to three-celled. The style is short, the stigma 2- or 3-lobed, with two ovules per cell. Fertile and sterile flowers are produced together in terminal, spreading, compound cymes—the sterile being usually fewer and falling after the anther cells mature. Flowers are produced in May and June.
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The outside surface of the inner petals is slightly hairy while the inner surface is dense with long hairs. Its flowers have more than 100 yellow stamen that are 1 by 0.5-0.6 millimeters. Its flowers have up to 8 hairy carpels that are 1.2-1.5 by 0.4-0.6 millimeters. The carpels have 8-10 ovules arranged in two rows.
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Their anthers are versatile (swinging freely) and oblong and attach to the filament at the back (dorsifixed). The pollen is bisulcate (two grooves). The inferior ovary is subglobose (slightly flattened sphere) and trilocular (three-lobed or three locules), with one to four ovules in each loculus. The style is filiform, straight or declinate and has an obscurely tricuspidate (three tipped) stigmatose apex.
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There is great variation in pollen tubes in angiosperms and many model plants like petunia, Arabidopsis, lily and tobacco plants have been studied for intraspecific variation and signaling mechanisms. In flowering plants, a phenomenon called polyambry can occur where many ovules are fertilized and overall fitness of the organism is yet to be studied with respect to rate of pollen tube growth.
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After seeds have been disseminated Abert's squirrels are dependent on inner bark, which forms the bulk of the diet from November to April. The soft inner tissue of small apical buds is also a preferred item. In May, staminate buds and cones and immature ovules are consumed as available. New staminate cones are entirely consumed; only the pollen is eaten from dried cones.
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Schisandaceae are pollinated predominantly by nocturnal gall midges that lay their eggs in the male and female flowers (in Schisandraceae species with unisexual flowers) or the male-stage and female-stage flowers (in species with bisexual flowers). The larvae of these midges develop in the floral tissue once it has dropped to the ground, feeding on floral exudates (not ovules or pollen).
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Extending out from a central axis are microsporophylls (modified leaves). Under each microsporophyll is one or several microsporangia (pollen sacs). The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which, when fertilized by pollen, become seeds. The female cone structure varies more markedly between the different conifer families, and is often crucial for the identification of many species of conifers.
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The ovules are attached to the partition, near its top. The two stigmas are short and attached directly to the apex of the ovary. The fruit is a capsule, 2.5 to 3.5 cm long and 1.5 to 2.5 cm wide, containing one, or rarely, two seeds. The capsule breaks up and its pieces fall, leaving the seed and the surrounding endocarps.
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The petioles are 18–30 cm long, and armed with sharp spines at the base. The female cones are open, with sporophylls 12–18 cm long, with four to six ovules per sporophyll. The lamina is lanceolate, with spined dentate margins and an apical spine. The sarcotesta is orange-brown, the sclerotesta short ovoid to globular, with a network of shallow grooves.
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A number of studies over the years have noted various morphological, developmental and embryological characters at variance with the Geraniales (as well as other groups to which Limnanthaceae have been assigned). Maheshwari and Johri (1956) conducted an extensive investigation of the morphology of Floerkea noting that, among other things, the herbaceous habit, gynobasic style, unusual type of tetrasporic embryo sac and basal parietal placentation of the unitegmic, tenuinucellate ovules differ from the Geraniales which has among its woody to herbaceous members, (at most) lobed syncarpous gynoecia, monosporic embryo sacs, generally axile placentation and bitegmic, crassinucellate ovules. Additionally the fruit type of Limnanthaceae, a schizocarpic nutlet, is unlike anything in the Geraniales most of which produce capsules. They also found a number of key differences between Limnanthaceae and Sapindales, and concluded that Limnanthaceae should be given their own order.
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American Journal of Botany, 57: 50-61. Like the ovules, the synangia were attached to the underside of pinnules that did not differ significantly in form from those of the purely vegetative fronds, and so can give a superficially similarity to fertile fern fronds. Unlike ferns, however, these pollen-organs produced monolete, bisaccate pollen (fossil genus Vesicaspora) bearing some similarity to the pollen of many conifers.
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The flower is tubular, sometimes narrowing at the top, and varies in color; various shades off red, white, and yellow appear in different species. A hairy belt of varying width appears above the stamens. The tube of the flower varies in length from 9 to 60 mm across the genus. The ovary of the flower is composed of two carpels, each containing numerous ovules.
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As the pollen tube continues to grow towards the ovules, the male sperm remains in the apical region and is transported to the female ovule. The pollen tube elongates at a rate comparable to neurite development An example of positive and negative chemotropism is shown by a plant's roots; the roots grow towards useful minerals displaying positive chemotropism, and grow away from harmful acids displaying negative chemotropism.
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The carpels have 6-12 ovules. Its fruit occur in clusters of 4-6 on pedicels that are 10 by 2 millimeters and covered in sparse, fine hairs. The smooth, sparsely hairy, oblong fruit are 14-30 by 7.5 millimeters. The fruit are attached to the pedicel by stipes that are 3-3.5 by 2 millimeters and covered in sparse, grey-brown, fine hairs.
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The inner petals have a basal claw and a rhomboidal blade. Its flowers have more than 100 yellow stamens that are 1-1.2 by 0.4-0.6 millimeters. Its flower have 4-6 carpels that are 1.3-1.5 by 0.6-0l8 millimeters and covered in fine hairs. Its stigma is shaped like a narrow, inverted cone. The carpels have 8-12 ovules arranged in two rows.
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Its stalked seeds would have grown from a central receptacle, and the entire flower of Williamsonia would have been surrounded by protective bracts (which are often the only part of the plant to undergo fossilization). The cones of Williamsonia were monosporangiate. They were "cup shaped" and could be up to in diameter. As many as 25-50 ovules could be present in each cone.
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Its flowers have 6 stamens with filaments that are 8.3-8.7 by 2.7-3 millimeters and anthers that are 3 millimeters long. Its flowers have a single thread-like style that is 6 centimeters long and topped by a 3-lobed stigma. Its flowers have an ellipsoid ovary that is 7.5-8 by 4.3-5 millimeters with 3 chambers. Each of the ovary chambers has numerous ovules.
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Glaucous leaf waxes may be either present or absent, causing plants to be either blue or green in overall appearance. It is suited to tropical regions which have a seasonally dry climate. This strikingly distinctive and widespread species was only first recognised in 1978 by Australian botanist John Maconochie. The specific name, pruinosa, means "covered with powder" and aptly describes the blue-white ovules of this plant.
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Its flowers have numerous stamen with anthers that dehisce longitudinally. The connective tissue between the lobes of the anthers extends upward and outward to form a fleshy head. Its fruit have multiple hairless carpels with, wedge-shaped styles, 1-2 ovules each, and outwardly glandular tips that are recurved and have a ventral suture. Its oval, hairless fruit are up to 3 centimeters long.
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Ovules 50-100 per ovary. Fruit are oblong to oblong-linear, strongly 4-angled, slightly angustiseptate, (5-)7-10(-14) × 2–3 mm, smooth, erect and often appressed to rachis, straight; valves with a prominent midvein and slightly winged keel, outside with transversely oriented malpighiaceous trichomes, inside glabrous; style slender, (4-)5-10(-12) mm, cylindric; stigma strongly 2-lobed, with lobes often divergent.
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The current directors Dr. Leonardo Marquès Amorós and Dr.Marisa López-Teijón joined in 1987. In 1989 Institut Marquès set up the first FIV lab which was renovated and expanded in 2009 with top of the line equipment in Reproductive Biology. In 2005 the clinic created a Preimplantation Genetic Diagnosis (DGP) lab at CIMA clinic, instigating in the genetic analysis of embryos, ovules and spermatozoids.
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The flowers are hermaphrodite, in one to many whorls, in umbels, racemes or panicles; they have six stamens, and six to nine carpels arranged in a whorl, connate at the base, each with two to many ventral ovules; The styles are terminal. The fruit is a whorl of follicles; the follicles are laterally compressed, stellately radiating, with a more or less elongated apical beak.
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A "perfect flower", this Crateva religiosa flower has both stamens (outer ring) and a pistil (center). The principal purpose of a flower is the reproduction of the individual and the species. All flowering plants are heterosporous, that is, every individual plant produces two types of spores. Microspores are produced by meiosis inside anthers and megaspores are produced inside ovules that are within an ovary.
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In both groups, the flowers usually bear numerous stamens, and in the ovary, the placentation is mostly axile. In the ovules, the nucellus is often thin, and the outer integument is usually thicker than the inner.Peter K. Endress, Charles C. Davis, and Merran L. Matthews. 2013. "Advances in the floral structural characterization of the major subclades of Malpighiales, one of the largest orders of flowering plants".
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It is not clear whether the presence or absence of endosperm is the ancestral state in Ochnaceae. For a long time, the subfamily Ochnoideae was divided into two groups based on this character alone. In such a classification, the group containing endosperm would be paraphyletic over Ochneae because it would contain Testulea, Philacra, and Luxemburgia. The number of ovules per carpel varies widely in Ochnaceae.
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From the perspective of the source-sink hypothesis, each embryo acts as a sink, or recipient, of finite resources from roots and photosynthetic tissues. Since resources are limited, the number of existing ovules would be greater than the number of seeds the maternal plant can support, leading to competition for resources. Embryos may compete for resources by producing phytohormones involved in metabolism (such as auxin).
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The filaments are threadlike, usually pale brown, and often bald. The pistillate (female) flowers are also without calyx or corolla, and consist of a single ovary accompanied by a small, flat nectar gland and inserted on the base of a scale which is likewise borne on the rachis of a catkin. The ovary is one-celled, the style two-lobed, and the ovules numerous.
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The leaf petioles are armed with spines in younger individuals (a few millimetres long) with this trait being lost in older individuals. The female cones are open type sporophylls 25–50 cm long, brown, each with 6-12 ovules each. The lamina is triangular ending in a sharp narrow spine. The male cones are solitary, erect, 20–25 cm long and 12–15 cm diameter.
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Mature plants have around 50 leaves in the crown. The female cones open, with 13–22 cm long sporophylls with 2-4 ovules per sporophyll on a lanceolate triangular lamina with an apical spine. The sarcotesta has a yellow coating when ripe. The male cones are ovoid, orange, 11–20 cm long and 7.5–10 cm diameter, with upper half of cone drawn to a point.
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The petiole is armed with spines nearly over its entirety, with glabrous, glossy green leaflets angled forward about 70-80 degrees. The female cones are open, grey with orange hairs, with each sporophyll containing 6-8 ovules. The male cones are orange, narrowly ovoid. The name derives from the plant's vernacular name in the language of the Kaka tribe of the Sepik River estuary in New Guinea.
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The petiole is sometimes armed with spines, and terminates in a spine or pair of leaflets. The female cones are open, with sporophylls 7 cm long and 3.5–5 cm wide, and dense grey to orange tomentose, with 6-9 ovules per sporophyll. The sarcotesta is thick orange tomentose, and the sclerotesta flattened ovoid shaped. The male cones erect, narrow ovoid, with a broad apical spine.
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The female cones are open, with sporophylls 16–21 cm long, with two to four ovules per sporophyll. The lamina is narrowly triangular, with toothed margins and an apical spine. The sarcotesta is yellow-brown with a waxy coating, the sclerotesta ovoid and flattened. The male cones are solitary, ovoid, 16–20 cm long and 7–10 cm diameter, brown, and with an upturned apical spine.
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In the dog whelk, the growth of a penis in imposex females gradually blocks the oviduct, although ovule production continues. An imposex female dog whelk passes through several stages of penis growth before it becomes unable to maintain a constant production of ovules. Later stages of imposex lead to sterility and the premature death of the females of reproductive age, which can adversely affect the entire population.
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On the contrary, non-hermaphroditic plants are self- incompatible. Research has shown that a species can be either gynodioecious or self-incompatible, but very rarely is there a co-occurrence between the two. Therefore, gynodioecy and self-incompatibility tend to prevent each other’s maintenance. Self-incompatibility of plants helps maintain androdioecy in plants, since males are in competition with only hermaphrodites to sire ovules.
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Female specimens bear megaspores that are found in large numbers in the upper part of the stem, with the appearance of pinnate leaves that enclose the ovules, in clumps of 4. The seeds are oblong, 50–60 mm long, coated with an orange-brown tegument when ripe. The megasporophyll is a defining feature, with laminae which de Louriero described as "laciniate" (fringed with lateral narrow pointed lobes).
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Individual plants of this species have ovaries with two chambers, each of which contains one ovule. The ovules are located near the base of the flower and are erect, or they are attached horizontally near the base. The style (the structure that connects the ovary to the stigma) is terminal. The stigma can be asymmetrical, bent backwards or downwards, or consist of two lobes.
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Late-acting self-incompatibility (LSI) is the occurrence of self- incompatibility (SI) in flowering plants where pollen tubes from self-pollen successfully reach the ovary, but ovules fail to develop. Mechanisms that might cause late-acting self-incompatibility have yet to be elucidated. One hypothesis is that the occurrence of LSI is caused by early-acting inbreeding depression where the expression of genetic load causes self-fertilized embryos to abort.
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The ovary is inferior with 2–15 united carpels containing a single locule with numerous ovules on parietal placentas which either protrude nearly to the centre of the ovary or are incompletely developed. Fruits are globular to linear, dry or pulpy, dehiscent or more usually indehiscent and opening by decay of the pericarp. Seeds are normally numerous with straight embryos and no endosperm. Pollination can be extremely specialised.
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Ten to twenty (or many more) stamens inserted below the ovary, spirally arranged and forming a ball or flat-topped mass with short and stout filaments and linear to oblong anthers which face outward and open longitudinally. Each flower can have from one to many pistils, distinct to connate, with stigmas distinct. Marginal placentation, each pistil bearing one locule, with one to many ovules. Style short and thick, with terminal stigma.
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At at least three points in the history of Leavenworthia there have been transitions between mating systems, in which self-incompatible plants evolved self-compatibility, developing the ability to fertilize their own ovules. This process has inspired studies of the genetics of the genus, which may help explain how such changes occurred. Self-incompatibility is the ancestral state of the genus, and it has been lost several times.Busch, J. W. (2005).
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Quantity of ovules (seedbuds) in the ovary and seeds in the pod was also accepted as the criterion for this division. Most of the described species from the eastern and western hemispheres were referred to subgen. A. Eulupinus. Subgen. B. Platycarpos included several annual species from the eastern hemisphere with two seedbuds and seeds in the bean (the same species, as the one specified by S. Watson). Subgen.
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Its flowers are terminal or axillary, bisexual, solitary or in an up to nine-flowered open panicle, pedicel with small paired bracts. It has four decussate sepals sub-orbicular, persistent and variously enlarged and thickened in fruit. Stamens are numerous, free or connate only at the base, ovary superior (1-2 celled) each cell with one to two axillary ovules. They are slender with a peltate to four-lobed stigma.
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In plant ovules, the chalaza is located opposite the micropyle opening of the integuments. It is the tissue where the integuments and nucellus are joined. Nutrients from the plant travel through vascular tissue in the funiculus and outer integument through the chalaza into the nucellus. During the development of the embryo sac inside a flowering plant ovule, the three cells at the chalazal end become the antipodal cells.
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Next inwards there are numerous stamens, which produce pollen grains, each containing a microscopic male gametophyte. Stamens may be called the "male" parts of a flower and collectively form the androecium. Finally in the middle there are carpels, which at maturity contain one or more ovules, and within each ovule is a tiny female gametophyte. Carpels may be called the "female" parts of a flower and collectively form the gynoecium.
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The Asphodeloideae are distinguished by a general presence of anthraquinones, simultaneous microsporogenesis, atypical ovules morphology, and the presence of an aril. Asphodeloideae also have a characteristic secondary growth by means of a secondary thickening meristem. This character, however, is also found in other taxa in the Asparagales, including Agavaceae, Iridaceae, and Xanthorrhoeoideae. It is confined to Asparagales among the monocots and is believed to have evolved independently in most families.
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Bombylius major visiting E. mediohispanicum flower Flowers have a tetradynamous androecium, with four long and two short stamens. Each flowers contain a variable number of ovules, ranging between 15 and 30 approx. Flowers have a non-fused corolla tube formed by the union of the petals and sepals. Flowers produce minute amount of nectar in four nectaries located in the base of the corolla tube, around the ovary.
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The fruit of Primulaceae begins as an ovary and inside it are the future seeds (ovules). These are attached to a central axis without any partitions between them (an arrangement called free central placentation; see item 7 in the figure), and they are bitegmic (having a double protective layer around each ovule). Unlike in most other families of Ericales, both layers form the opening at the top (the micropyle).
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The connective tissue between the lobes of the anther extends upward for 0.6-0.7 millimeters to form a tapering tip. Its flowers have 50-100 carpels with oblong, flattened ovaries that are 2-2.2 millimeters long and covered in dense, matted, silky, golden hairs. Each ovary has 1-2 ovules. Its flattened styles are 4.5-5 millimeters long and come to a tapering tip that exudes sticky mucilage.
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The nucellus (plural: nucelli) is part of the inner structure of the ovule, forming a layer of diploid (sporophytic) cells immediately inside the integuments. It is structurally and functionally equivalent to the megasporangium. In immature ovules, the nucellus contains a megasporocyte (megaspore mother cell), which undergoes sporogenesis via meiosis. In the megasporocyte of Arabidopsis thaliana, meiosis depends on the expression of genes that facilitate DNA repair and homologous recombination.
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The pistillate flowers are also yellow with three cupped sepals and three longer, imbricate petals. When staminodes are present there are three, joined in a ring; the gynoecum is ovoid, triocular and triovulate. The three stigmas are recurved with elongated, laterally attached ovules. The large fruit is round or slightly egg shaped, maturing to bright red or orange in color, with a fleshy mesocarp and a membranous endocarp.
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The apices of the inner petals converge but are not fused. The outer surfaces of the inner petals are densely covered in fine hairs; the inner surface is covered in woolly hairs near tip. Its flowers have numerous oblong stamen are 0.9-1.4 by 0.6-0.7 millimeters. Its flowers have up to 16 carpels that are 0.9-1.5 by 0.7-0.9 millimeters. Its ovaries have 5-10 ovules.
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The pollen is elliptic and monosulcate with finely reticulate, tectate exine. The pistillate are smaller, the three distinct sepals are ovate, broadly imbricate, with pointed tips, the three petals are similar but with longer tips. The staminodes are united in an irregular ring, the gynoecium is triocular, triovulate with short trifid stigmas and laterally attached ovules. The fruit is egg-shaped, with three pores, green to yellow, carrying a single seed.
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So do the three most basal clades of Sauvagesieae, namely Blastemanthus, Fleurydora, and a clade of four genera that have five carpels and many ovules per carpel (Godoya, Rhytidanthera, Krukoviella, and Cespedesia). Poecilandra has poricidal anther dehiscence, but in its sister genus, Wallacea, the anthers open by longitudinal slits. In the rest of Sauvagesieae, anther dehiscence is various. In Schuurmansia, Schuurmansiella, and Adenarake, the anther dehiscence is apically longicidal.
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The styles are filiform (threadlike) or clavate (clubshaped), thickened at their tip, being globose to rostellate (beaked). The stigmas are head-like, narrowed or often beaked. The flowers have a superior ovary with one cell, which has three placentae, containing many ovules. After flowering, fruit capsules are produced that are thick walled, with few to many seeds per carpel, and dehisce (split open) by way of three valves.
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The racemes are few-flowered, short, erect, crowded in axils of upper leaves so as to form a large terminal inflorescence stamens barren; the ovary is superior, unilocular, with marginal ovules. The fruit is a short legume, 7.5–11 cm long, 1.5 cm broad, oblong, obtuse, tipped with long style base, flat, thin, papery, undulately crimpled, pilose, pale brown. 12-20 seeds per fruit are carried each in its separate cavity.
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Adults enter through the fig ostiole, a narrow, bract-lined passage, then pollinate and attempt to oviposit on the flowers. Flower ovules that receive an egg become galled and the larvae consume the gall tissue. Pollinated flowers missed by the wasps produce one seed each. The adult offspring emerge from the gall and mate in the fig, before the winged female wasps disperse, carrying the flower pollen with them.
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Their roots have small secondary roots. The coralloid roots develop at the base of the stem at or below the soil surface. Male and female sporophylls are spirally aggregated into determinate cones that grow along the axis. Female sporophylls are simple, appearing peltate, with a barren stipe and an expanded and thickened lamina with 2 (rarely 3 or more) sessile ovules inserted on the inner (axis facing) surface and directed inward.
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This plant is known as conifer because the reproductive portions of this species are organized in yellow-green cones. The male, staminate cones are oval, 3-8mm long, organized in dense clusters, with 3-6 stipitate microsporangia. The female, or ovulate cones are found at the nodes of the stems. The ovulate cones are oval, up to 10mm long, with 4-5 pairs of overlapping yellow bracts surrounding two ovules.
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In essence, they have a lower, underground component and an upper, aerial component. The underground part develops roots that seek water and nourishment from the soil, while the upper component, or shoot, grows toward the light and develops a plant stem, leaves and specialised reproductive structures (sporangia). In angiosperms, the sporangia are located in the stamen anthers (microsporangia) and ovules (megasporangia). The specialised sporangia bearing stem is the flower.
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However, there is a strong possibility that this reconstruction was based on the chance finds of ovules having been preserved just lying on a piece of pinna rather than in organic attachment to it. A number of cases are now coming to light that suggest that the seeds were borne in clusters on relatively slender, branching axes, and that these trusses of ovules would have been produced from the top of the trunk among the crown of fronds. The seed megaspore was surrounded by two layers of tissue: a vascularised nucellus and a usually three-layered integument; the nucellus and integument were completely free except at the base of the ovule. There has been some debate as to the exact homologies of these tissues, and it has been argued that the vascularised nucellus was in fact the nucellus and integument that have become fused together, and that the 'integument' was homologous to a cupule that contained only one ovule.
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The petals are clawed, sometimes cleft at the tip or finely dissected. Flowers have five to ten stamens, free and opposite the petals, with the anthers usually basifixed and opening by lengthwise slits. The ovary is inferior to semi-inferior with two (sometimes three) carpels usually fused at the base, sometimes free, each topped with stylodium and capitate stigma. The ovules are few to many, with axile or parietal placentation and two to three styles.
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A study by Lippow and Wyatt reported that species that have LSI create offspring that can be split into different groupings of compatibility and incompatibility based on Mendelian inheritance, which is something that can be demonstrated with plants that have typical SI mechanisms. It is also reported that some plants lack conventional SI mechanisms, yet ovules failed to develop at all, which is unexpected if the mechanism were to be due to lethal alleles.
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The stamens are anterior and are longer than the staminodes. The medial stamen differs in size and form from the lateral two, and when a central staminode is present it also differs from the other staminodes. The ovaries are bi- or trilocular and one to two ovules is present per locule. The fruit is a capsule that is typically bi- or trilocular, but in rare cases may be unilocular, and it is bi- or trivalved.
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There are mostly two to four rarely up to eight carpels. The ovary is mostly green, but sometimes purple, is topped by a yellow-green, yellow, red, or purple-red stigma, and contains seven to seventeen ovules in each carpel. These develop into fruits (so-called follicles) which are long ovoid in shape, 2-3½ × 1-1½ cm, which are brown when ripe in August, and contain between one and six brown-black seeds each.
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Vigorous and growing rapidly in woods, scrub, hillsides, and hedgerows, blackberry shrubs tolerate poor soils, readily colonizing wasteland, ditches, and vacant lots. The flowers are produced in late spring and early summer on short racemes on the tips of the flowering laterals. Each flower is about 2–3 cm in diameter with five white or pale pink petals. The drupelets only develop around ovules that are fertilized by the male gamete from a pollen grain.
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Once the pollen tube reaches an ovule, it bursts to deliver the two sperm cells. One of the sperm cells fertilizes the egg cell which develops into an embryo, which will become the future plant. The other one fuses with both polar nuclei of the central cell to form the endosperm, which serves as the embryo's food supply. Finally, the ovary will develop into a fruit and the ovules will develop into seeds.
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The tight ostiolar enclosure at the apex of syconia makes them highly pollinator-specific. When receptive to pollen, the ostiole slightly loosens, allowing the highly specialized wasps to enter through it. The wasps lose their wings in the process, and once inside they pollinate female flowers as they lay their eggs in some ovules, which then form galls. The wasps then die and larvae develop in the galls, while seeds develop in the pollinated flowers.
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The complex mechanisms that orchids have evolved to achieve cross-pollination were investigated by Charles Darwin and described in Fertilisation of Orchids (1862). Orchids have developed highly specialized pollination systems, thus the chances of being pollinated are often scarce, so orchid flowers usually remain receptive for very long periods, rendering unpollinated flowers long-lasting in cultivation. Most orchids deliver pollen in a single mass. Each time pollination succeeds, thousands of ovules can be fertilized.
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Plantago aucklandica differs from all other species of Plantago that are indigenous to New Zealand by its large leaves with up to seven veins, axillary hairs, wide petioles, and long spikes with up to 132 flowers. It has only two ovules (one of which aborts) in each ovary, and its seeds have low rounded protuberances on the ventral surface, whereas all other New Zealand native species have seeds with a networked ventral surface.
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The corolla and calyx have four lobes each, with eight stamens inserted at the base of the disc, the filaments being connate at their base. The ovary is superior and sessile; it has four lobes and four locules, each containing two collateral ascending ovules. The stigma is simple and the style extends further than the stamens. The fruit is an inflated membranous capsule, 3–5 cm across, each locule forming a distinct lobe.
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In gymnosperms, which do not form ovaries, the ovules and hence the seeds are exposed. This is the basis for their nomenclature – naked seeded plants. Two sperm cells transferred from the pollen do not develop the seed by double fertilization, but one sperm nucleus unites with the egg nucleus and the other sperm is not used. Sometimes each sperm fertilizes an egg cell and one zygote is then aborted or absorbed during early development.
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Within the carpel the megasporangium form the ovules, with its protective layers (integument) in the megaspore, and the female gametophyte. Unlike the male gametophyte, which is transported in the pollen, the female gametophyte remains within the ovule. Most flowers have both male and female organs, and hence are considered bisexual (perfect), which is thought to be the ancestral state. However, others have either one or the other and are therefore unisexual, or imperfect.
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Anthers are basifixed and open lengthwise. The flowers are bisexual, less commonly unisexual (more or less dioecious). Ovaries superior to partially inferior, with carpels equal to the number of petals, each forming a single locule, superior, free or almost so, basally with a small to conspicuous basal nectary scale, gradually tapering to a short to long style with few to many ovules. The fruit is usually capsular with dehiscent follicles, opening along the carpal suture and many seeded.
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The Medullosales is an order of pteridospermous seed plants characterised by large ovules with circular cross-section, with a vascularised nucellus, complex pollen-organs, stems and rachides with a dissected stele, and frond- like leaves. Their nearest still-living relatives are the cycads. Most medullosaleans were small to medium-sized trees. The largest were probably the trees with Alethopteris fronds - these fronds could be at least 7 metres long and the trees were perhaps up to 10 metres tall.
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The aerial roots of the plant are red when they first begin growing and later turn a dark brown with age. The spadix of Philodendron crassinervium gets to about 20–25 cm long and is covered by a spathe that is white with shades of a dark red towards the bottom where the spadix emerges. The berries produced contain eight axile ovules in each ovary locule. There are some species that resemble Philodendron crassinervium, such as Philodendron longilaminatum.
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"Most of the fruits were obtained by dissolving in hydrofluoric acid a single very small fragment of shale collected from Cape Stewart" The maceration of the fruits dissolves the main cells wall and leave the cuticle and interior cell organs. This allowed Harris to look closely at the ovules located inside. Upon close inspection of the ovule, whole pollen grains were found inside the micropylar canal. This is typical of a gymnosperm reproduction, not an angiosperm.
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It grows together with Adonis vernalis, Cytisus reverchonii, Quercus rotundifolia, Pinus nigra, Pinus pinaster, and Polygonatum odoratum. Plants that grow in different regions vary in the number of flowers per plant, in petal size, the number of stamens per flower, and the number of ovules in each carpel. These differences are related to the dominant pollinators, such as honey bees and bumble bees (Bombus terrestris) in the Sierra de Cazorla and smaller halictid bees in the Sierra de Jaén.
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The mating systems found in genus Leavenworthia have been studied extensively because they are variable and have changed several times in the evolutionary history of the group. Some species are self-compatible, while others are self-incompatible. L. exigua, L. torulosa, and L. uniflora are self-compatible, able to produce seed from ovules fertilized by their own pollen. In L. alabamica and L. crassa, separate populations of self-compatible and self-incompatible individuals have been observed.
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Each carpel in Ranunculus species is an achene that produces one ovule, which when fertilized becomes a seed. If the carpel contains more than one seed, as in Eranthis hyemalis, it is called a follicle. Two or more carpels may be fused together to varying degrees and the entire structure, including the fused styles and stigmas may be called a pistil. The lower part of the pistil, where the ovules are produced, is called the ovary.
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In many plants, the development of the flesh of the fruit is proportional to the percentage of fertilised ovules. For example, with watermelon, about a thousand grains of pollen must be delivered and spread evenly on the three lobes of the stigma to make a normal sized and shaped fruit. Cross- fertilisation and self-fertilisation represent different strategies with differing benefits and costs. An estimated 48.7% of plant species are either dioecious or self-incompatible obligate out-crossers.
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The most likely cause of undeveloped ovules is inadequate pollinator visits. Even a small change in conditions, such as a rainy day or a day too hot for bees to work after early morning, can reduce the number of bee visits to the flower, thus reducing the quality of the fruit. Incomplete drupelet development can also be a symptom of exhausted reserves in the plant's roots or infection with a virus such as raspberry bushy dwarf virus.
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Some flowers are self-pollinated and use flowers that never open or are self-pollinated before the flowers open, these flowers are called cleistogamous. Many Viola species and some Salvia have these types of flowers. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on the same plant may not appear or mature at the same time, or pollen from the same plant may be incapable of fertilizing its ovules.
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It is also highly unlikely that they were close relatives of gymnosperms, cycads or ginkgos, because these lineages were already established and distinct in the Late Permian. Vegetative leaves of Emplectopteris were at one time included in this group. However, they had ovules attached to the underside of the fronds and are now placed in their own family (Emplectopteridaceae) within the Callistophytales. Some prefer to refer to the presumed "core" taxa of this group as Gigantonomiales.
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Depending on the organ cultured, it may be referred to as either embryo, ovule, or ovary culture. Ovule culture or in ovolo embryo culture is a modified technique of embryo rescue whereby embryos are cultured while still inside their ovules to prevent damaging them during the excision process. Ovary or pod culture, on the other hand employs the use of an entire ovary into culture. It becomes necessary to excise the entire small embryo to prevent early embryo abortion.
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Fertilisation takes place when the nucleus of one of the sperm cells enters the egg cell in the megagametophyte's archegonium. In flowering plants, the anthers of the flower produce microspores by meiosis. These undergo mitosis to form male gametophytes, each of which contains two haploid cells. Meanwhile, the ovules produce megaspores by meiosis, further division of these form the female gametophytes, which are very strongly reduced, each consisting only of a few cells, one of which is the egg.
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Plants in the genus Nematolepis are shrubs or small trees with their stems, leaves and sepals covered with shield-like scales. The leaves are simple and arranged alternately. The flowers are arranged singly or in cymes in leaf axils, and have five sepals, five partly overlapping petals and ten stamens, all free from each other in most species. The five carpels are free from each other, each with two ovules and the stigma is not differentiated from the style.
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Increasing the opportunity for paternity by distributing pollen among pollinators may take different routes in different systems, and any of these possibilities can be viewed in a sexual selection context . The gynoecium is also affected by sexual selection. Every part from the ovaries, styles, stigma, and carpels can be faced with the pressures of sexual selection. In ovule packaging, the intensity of pollen competition depends in part on the number of pollen grains relative to the number of ovules.
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However, the growth of the pollen tubes may be detained at some point between the stigma and the ovules, in such a way that fertilization does not take place. This mechanism of reproductive isolation is common in the angiosperms and is called cross- incompatibility or incongruence. A relationship exists between self- incompatibility and the phenomenon of cross-incompatibility. In general crosses between individuals of a self-compatible species (SC) with individuals of a self-incompatible (SI) species give hybrid offspring.
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Presumably pollination was at an early stage of cupule and ovule development, before full inflation of the cupules. While Thomas's original idea led many scientist to believe that Caytoniales may have been angiosperms, Harris's further research disproved this theory. The enclosure of ovules in Caytoniales has nevertheless been considered an early stage in evolution of the angiosperm double integument, and the carpels formed from an elaboration of their stalk (Fig. 5). Other theories for the origin of angiosperms derive them from Glossopteridales (Fig.
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Pollination and fruit formation depend on meiosis. Meiosis is central to the processes by which diploid microspore mother cells within the anther give rise to haploid pollen grains, and megaspore mother cells in ovules that are contained within the ovary give rise to haploid nuclei. Union of haploid nuclei from pollen and ovule (fertilization) can occur either by self- or cross-pollination. Fertilization leads to the formation of a diploid zygote that can then develop into an embryo within the emerging seed.
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Location of ovules inside a Helleborus foetidus flower In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the integument, forming its outer layer, the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center. The female gametophyte — specifically termed a megagametophyte— is also called the embryo sac in angiosperms. The megagametophyte produces an egg cell for the purpose of fertilization.
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SEM image of pollen tubes growing from Lily pollen grains.A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life cycle. The pollen tube acts as a conduit to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms.
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This behavioral response allows pollen tubes to attack flower pistils and drop off sperm cells to ovules for fertilization. Carlos Agudelo and colleagues investigated the relationship between electrical signaling and pollen tube growth. The model organism used by the researcher was Camellia japonica pollen, because it displayed a differential sensitivity to the electrical fields when different parts of the tube were exposed. This flower is found in the wild areas of mainland China and Taiwan at elevations of 300–1100 meters.
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Mating occurs during the spring in sun spots on moose carcasses. Females with unfertilized ovules lie in sunny spots and males attempt to woo the females while fighting amongst each other for access. A male waltzing fly will try to attract a female by dancing side-to-side in front of her and lifting the front portion of his body upwards. If the female accepts him as a mate, she raises her forelegs and he touches his forelegs to hers.
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Unlike most biological groupings, it is difficult to find many common characteristics between all of the members of the gnetophytes. The two common characteristics most commonly used are the presence of enveloping bracts around both the ovules and microsporangia as well as a micropylar projection of the outer membrane of the ovule that produces a pollination droplet,Judd, W.S.; Campbell, C.S.; Kellogg, E.A.; Stevens, P.F.; and Donoghue, M.J. (2008) Plant Systematics: A Phylogenetics Approach. 3rd ed. Sunderland, Massachusetts, USA: Sinauer Associates, Inc.
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The resin of the Burseraceae is nonallergenic and two ovules per carpel occur, whereas the resin of the Anacardiaceae can be allergenic or poisonous and one ovule per carpel is found. The Burseraceae-Anacardiaceae clade is sister to a robust cluster of three other families, the Sapindaceae-Aceraceae-Hippocastanaceae clade. The Rutaceae-Meliaceae-Simaroubaceae clade is sister to the Burseraceae-Anacardiaceae and Sapindaceae-Aceraceae-Hippocastanaceae clade. The rbcL technique is supported and considered acceptable until other methods become better developed for the analysis.
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In warm weather this takes about 48 hours but in cold weather it may take a week, and by that time, the ovule may have passed the stage where it is receptive. If fewer than about 35 ovules are fertilised, the fruit may not be able to develop and will fall prematurely. Frost can damage both unopened and open flowers when the temperature falls below . The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged.
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Leaflets obovate-oblong to oblong-cuneate, thinly coriaceous, coarsely serrate-dentate. Flowers usually unisexual; inflorescences are compound umbels with 8-20 primary branchlets up to 10 cm long, 15-20 secondary rays, umbellules with 10-15 flowers in each. Calyx truncate or obscurely 5-toothed; flowers 5mm in diameter, sweet-scented; petals 5, white to pink flushed, ovate to triangular, acute; stamens 5; ovary 2-loculed, each containing 1(-2) ovules; style branches 2, spreading. Fruit fleshy, very dark purple, laterally compressed, 5–8 mm diam.
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The first seed plants, pteridosperms (seed ferns), now extinct, appeared in the Devonian and diversified through the Carboniferous. They were the ancestors of modern gymnosperms, of which four surviving groups are widespread today, particularly the conifers, which are dominant trees in several biomes. The name gymnosperm comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), as the ovules and subsequent seeds are not enclosed in a protective structure (carpels or fruit), but are borne naked, typically on cone scales.
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The three inner tepals can be closed firmly, raising the question of how pollinators might reach the stigma inside to deposit pollen. In a study of the interaction between pollinators and Albuca flowers, leafcutter bees were observed prying open the tepals and squeezing through to obtain the nectar inside. In the process, they left pollen on the tips of the tepals, where it absorbed fluid, germinated, and fertilized ovules. This was the first known case of flower petals performing the function of the stigma.
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Mechanism to prevent selfing and allowing compatible pollen to grow a pollen tube for fertilization to take place Once the pollen grain is recognized and hydrated, the pollen grain germinates to grow a pollen tube. There is competition in this step as many pollen grains may compete to reach the egg. The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. Only compatible pollen grains are allowed to grow as determined by signaling with the stigma.
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There is one superior pistil that consists of two carpels that may either sit directly above the base of the stamens or on a stalk. It initially consists of only one cavity but during its further development a thin wall grows that divides the cavity, both placentas and separates the two valves (a so-called false septum). Rarely, there is only one cavity without a septum. The 2–600 ovules are usually along the side margin of the carpels, or rarely at the top.
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There are five stamens; in some species they are free from the tube of the corolla, but in others they grow from near the base of the tube. The anthers, and in some species the upper parts of the filaments of the stamens, are joined into a ring around the style. The tips of the anthers are bearded with little brushes of white hair. The ovary is inferior and more or less fused to the calyx; it has two locules, each containing many small ovules.
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Trigonocarpus, the seed/ovule of Medullosales such as Macroneuropteris In 1938, W. A. Bell studied the Sydney Coalfield in Nova Scotia, and suggested that the large fossilized seeds called Trigonocarpus noeggerati could be the ovules of Macroneuropteris scheuchzeri. Erwin Zodrow in 2002 also noted that this ovule fossil was commonly in physical association with M. scheuchzeri foliage. Specimens of Trigonocarpus can be quite large. The largest recorded was 10 cm and has been noted as the largest ovule produced by a non-angiosperm seed-plant.
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The number of carpels is described by terms such as tricarpellate (three carpels). Carpels are thought to be phylogenetically derived from ovule-bearing leaves or leaf homologues (megasporophylls), which evolved to form a closed structure containing the ovules. This structure is typically rolled and fused along the margin. Although many flowers satisfy the above definition of a carpel, there are also flowers that do not have carpels according to this definition because in these flowers the ovule(s), although enclosed, are borne directly on the shoot apex.
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Plant ovules with megasporocytes before meiosis: Gymnosperm ovule on left, angiosperm ovule (inside ovary) on right After megasporogenesis, the megaspore develops into the female gametophyte (the embryo sac) in a process called megagametogenesis. The process of megagametogenesis varies depending on which pattern of megasporogenesis occurred. Some species, such as Tridax trilobata, Ehretia laevis, and Alectra thomsoni, can undergo different patterns of megasporogenesis and therefore different patterns of megagametogenesis. If the monosporic pattern occurred, the single nucleus undergoes mitosis three times, producing an eight-nucleate cell.
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Androecium are often faced by the pressures of sexual selection. This is particularly evident when pollen is produced; there may be several sources of sexual selection on the ways that pollen is presented to pollen vectors. Because pollen is packaged in units that ensure that several to many pollen grains travel together as in pollinia, polyads, viscin threads, etc., pollen donors may be able to monopolize stigmas and the associated ovules by blocking access by other males, unless selection also favors compensating stigma enlargement.
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In 1810, Robert Brown published the genus Dryandra in his On the Proteaceae of Jussieu. Thirteen species were published, including Dryandra falcata (now Banksia falcata), but no infrageneric arrangement was proffered. Twenty years later, Brown published a further eleven species and the first infrageneric arrangement in his Supplementum primum prodromi florae Novae Hollandiae. By this time, Brown had observed the tendency in D. falcata for one of the two ovules in each follicle to abort, thereafter developing into a winglike appendage to the seed separator.
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Some authors have placed Butomus in the Limnocharitaceae because of its laminar placentation and follicular fruit, but it is now placed in the monospecific family Butomaceae. The Limnocharitaceae are closely related to the Alismataceae, but differ from them by the fully dehiscent fruit, numerous ovules per carpel, and laminar placentation. Members of both of these families have laticifers, petioles, a terminal pore on each leaf, a sepaloid calyx, and thin, evanescent petals. The family Limnocharitaceae was separated from the Alismataceae by Armen Takhtajan in 1954,Armen L. Takhtajan. 1954.
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The proposed advantages of LSI compared to normal SI mechanisms is that LSI would allow the maternal parent to evaluate the paternal genetic material and allow ovule development depending on the vigor of developing embryos or amount of resources available. On the other hand, plants with LSI may face a disadvantage from seed discounting, which results in a reduction in fecundity. When pollen tubes reach the ovule, they are no longer available to be fertilized by outcrossed pollen, meaning LSI still uses up ovules for potential outcrossing while other SI methods do not.
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Since LSI reactions are said to occur in the ovary and ovules, it is more difficult to researchers to determine where LSI reactions may occur to assess possible LSI mechanisms. Conventional SI reactions are much easier to observe, because they occur in the style or on the stigma. However, research has provided some evidence for the existence of late-acting self-incompatibility. Species noted to possibly have LSI form phylogenetic groupings in a similar fashion to how conventional SI is shared in other phylogenetic groups, suggesting that LSI may be derived from a common ancestor.
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The plant was known to botanists, including Dioscorides (, 40 AD – 90 AD) in his De Materia Medica () as Telephion (). Pliny, Gerard and Parkinson were among many later authors to describe Telephium. It was first formally described by Linnaeus in 1753, as one of 15 species of Sedum, Gray included it and related species as a section of the genus Sedum. These species differ markedly from the rest of that genus by a distinct ovary and ovules, flowering stems, leaves, inflorescence, flower parts, colour and blooming time and chromosome number.
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She became a lecturer at the University in 1936, allowing her to pursue her own studies. In 1938, Calder worked on the seed plants Calymmatotheca kidstonii and Samaropsis scotica, both from the Tournaisian age (345.3 to 359.2 million years ago) of the Lower Carboniferous (Mississippian). The two species were later studied further by Albert G. Long in 1959 and emended to Genomosperma kidstonii and Lyrasperma scotica. They became significant as one of the oldest known seed plants discovered with fossilised ovules, providing an important early glimpse into the evolution of reproduction in seed plants.
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It includes only a few species of small evergreen trees and shrubs species native to tropical South America.Kew World Checklist of Selected Plant FamiliesLissocarpa in IPNI, The International Plant Names Index Lissocarpa species share various characters with other members of Ebenaceae, e.g., the black color of roots and bark, extrafloral nectaries on abaxial leaf surfaces, a persistent calyx, unisexual flowers, biovulate carpels with pendulous ovules, and a similar wood anatomy producing a hard, dark heartwood timber similar to ebony. They are slow-growing trees found on a wide variety of soils and sites.
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Depending on the exact location, cone development can vary with North Island mountain pine producing cones more toward the October end of the range. By the end of November, the once juvenile reddish cones take on more brown character and begin to shed pollen. Around this same time, ovules grow at the tips of the branches and once fertilized by the pollen they develop a white aril at the base. Seeds begin to develop in the following months up until the fruiting season, which occurs from February to June.
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A syrphid fly (Eristalinus taeniops) pollinating a common hawkweed mining bee (Andrena lonicerae) pollinating a honeysuckle (Lonicera gracilipes). A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insect pollinators include bees, (honey bees, solitary species, bumblebees); pollen wasps (Masarinae); ants; flies including bee flies, hoverflies and mosquitoes; lepidopterans, both butterflies and moths; and flower beetles.
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The mechanism to abort self-pollinated fruits is not known, but cross-fertilised ovules grow faster from the start. By producing annually large amounts of fruits that are consumed by terrestrial fauna, the species also plays an important ecological role. It has been suggested that the agouti is responsible for most of the seed dispersal of H. stigonocarpa. Unlike many other species of the family Fabaceae, Hymenaea stiginocarpa is said to lack symbiontic soil bacteria, and therefore is unable to directly use the nitrate made by the bacteria from atmospheric nitrogen.
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Tree with ripe fruitsThe nectar-rich flowers of Hymenaea stiginocarpa open at night and are pollinated by several bat species, among which are the mostly fruit-eating Platyrhinus lineatus and Carollia perspicilata and the nectar specialist Glossophaga soricina. Hawkmoths also frequent the flowers, but seem ineffective in pollinating them. Self-pollinated seeds do not fully mature. Although the flower’s own pollen grains grow tubes and fertilise ovules as successfully as pollen from a different specimen, after seven or eight days the self-pollinated fruits fall from the tree.
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The scales are obovate, lobed, and fringed, membranous, hairy or smooth, and usually caducous. The male flowers are without calyx or corolla, and comprise a group of four to 60 stamens inserted on a disk; filaments are short and pale yellow; anthers are oblong, purple or red, introrse, and two-celled; the cells open longitudinally. The female flower also has no calyx or corolla, and comprises a single-celled ovary seated in a cup-shaped disk. The style is short, with two to four stigmata, variously lobed, and numerous ovules.
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These groups of anthers are held in bunches and are used as the flowers stamens. The anther groups are arranged into a triangle so that a gap forms between their pits and the beetles will proceed to fall down onto the stigma of the parasitic plant. The basal portion of the flower there is a cavity that houses the white ovules that will mature into seeds. Insects that pollinate the flowers do so by burying themselves in the sepals of the flowers through the very strong fibres that hold the sepals together.
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Seedless watermelon In botany and horticulture, parthenocarpy is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. Stenospermocarpy may also produce apparently seedless fruit, but the seeds are actually aborted while they are still small. Parthenocarpy (or stenospermocarpy) occasionally occurs as a mutation in nature; if it affects every flower the plant can no longer sexually reproduce but might be able to propagate by apomixis or by vegetative means. However, parthenocarpy of some fruits on a plant may be of value.
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In order for successful fertilization to occur, there is rapid tip growth in pollen tubes which delivers the male gametes into the ovules. A pollen tube consists of three different regions: the apex which is the growth region, the subapex which is the transition region, and the shank which acts like normal plant cells with the specific organelles. The apex region is where tip growth occurs and requires the fusion of secretory vesicles. There is mostly pectin and homogalacturonans (part of the cell wall at the pollen tube tip) inside these vesicles.
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Saraca indica, commonly known as asoka-tree, Ashok or simply Asoca, is a plant belonging to the subfamily Detarioideae of the family Fabaceae. The original plant specimen from which Carl Linnaeus described the species came from Java, but the name S. indica has been generally incorrectly applied to S. asoca since 1869. It can be distinguished from S. asoca by its non-clasping bracteoles, a lower number of ovules, slightly smaller pods, and a more eastern geographic distribution.‘Asoka’ – an important medicinal plant, its market scenario and conservation measures in India, table 1.
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Clindamycin preparations that are taken by mouth include capsules (containing clindamycin hydrochloride) and oral suspensions (containing clindamycin palmitate hydrochloride). Oral suspension is not favored for administration of clindamycin to children, due to its extremely foul taste and odor. Clindamycin is formulated in a vaginal cream and as vaginal ovules for treatment of bacterial vaginosis. It is also available for topical administration in gel form, as a lotion, and in a foam delivery system (each containing clindamycin phosphate) and a solution in ethanol (containing clindamycin hydrochloride) and is used primarily as a prescription acne treatment.
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The pistils of a flower are considered to be composed of carpels. A carpel is the female reproductive part of the flower, interpreted as modified leaves that bear structures called ovules, inside which the egg cells ultimately form and composed of ovary, style and stigma. A pistil may consist of one carpel, with its ovary, style and stigma, or several carpels may be joined together with a single ovary, the whole unit called a pistil. The gynoecium may consist of one or more uni- carpellate (with one carpel) pistils, or of one multi-carpellate pistil.
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Cycas balansae is a species of cycad in the genus Cycas, native to southwestern China (southeast Guangxi) and adjacent northern Vietnam (near Hanoi), where it occurs in dense mountain rainforests. It has a subterranean, unbranched stem 12–20 cm in diameter, bearing 4-9 leaves, each leaf 1.2-2.6 m long, pinnate with 90-160 leaflets, and armed with spines along the petiole. The leaflets are papery in texture, and angled forward at 80 degrees. The female cones are closed type, 8–12 cm long sporophylls with 2-4 ovules.
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The ovary, surrounding the ovules, develops into the fruit, which protects the seeds and may function to disperse them. The two central cell maternal nuclei (polar nuclei) that contribute to the endosperm, arise by mitosis from the same single meiotic product that gave rise to the egg. The maternal contribution to the genetic constitution of the triploid endosperm is double that of the embryo. In a study conducted in 2008 of the plant Arabidopsis thaliana, the migration of male nuclei inside the female gamete, in fusion with the female nuclei, has been documented for the first time using in vivo imaging.
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Homologous recombination (HR) is essential to cell division in eukaryotes like plants, animals, fungi and protists. In cells that divide through mitosis, homologous recombination repairs double-strand breaks in DNA caused by ionizing radiation or DNA-damaging chemicals. Left unrepaired, these double-strand breaks can cause large-scale rearrangement of chromosomes in somatic cells, which can in turn lead to cancer. In addition to repairing DNA, homologous recombination also helps produce genetic diversity when cells divide in meiosis to become specialized gamete cells—sperm or egg cells in animals, pollen or ovules in plants, and spores in fungi.
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The pollen producing organs consisted of clusters of elongate sacs formed into a variety of cup-, bell- and cigar-shaped configurations, assigned to various fossil genera including Dolerotheca, Whittleseya, Aulacotheca and Potoniea. Unlike with the ovules, there is good anatomical evidence that they were borne on the fronds, attached to the rachis. The pollen that they produce is strictly known as pre-pollen, as it germinated proximally and was thus intermediate in structure between pteridophytic spores and gymnospermous true-pollen. The pollen organs of the parispermacean species (fossil genus Potoniea) produced spherical pre-pollen with a trilete mark.
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It can grow in over a half meter of water, typically in marshes, swamps, rivers, or lake shores. Like many members of the genus, it cannot self-pollinate, and furthermore has a tendency for its ovules to abort, leading to fruits with few seeds. A phylogenetic study based on the nuclear ribosomal DNA region 5S NTS and the chloroplast region trnL-trnF, two commonly used gene regions for determining relationships, revealed that Commelina fluviatilis forms a clade with Commelina purpurea and Commelina welwitschii. Both of these relatives are African, share an unusual leaf anatomy, and have linear leaves that are often folded.
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The fruit of Aspalathus is a pod, and in the majority of species the ovary has two ovules that yield only one seed per pod. However, some pods are several-seeded. Various species of Aspalathus have been used in traditional medicines and as "bush teas", including Aspalathus tenuifolia, but it is difficult to know which sources to trust, because many specific names have been changed or confused in the past. Also, many uses were very local, and there was a good deal of confusion between different species, even sometimes with similar genera, such as Cyclopia, some species of which yield honeybush tea.
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Pittosporum obcordatum(2n=24) is dioecious, which means male plants contribute genes to next generation by pollen only, female plants pass on genes only via ovules. However, some males or females plants (6.6%) occasionally produce few seed capsules and become inconstant males or inconstant females. And about late September to early December the plant flowering and lasting about 3 weeks, but population in different altitude and latitude have slight different flowing time, for example, higher altitude and more inland plants flowering slightly later. December to May fruiting and the fruits and persist for a long time.
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Longitudinal section of female flower of squash showing pistil (=ovary+style+stigma), ovules, and petals. The petals and sepals are above the ovary; such a flower is said to have an inferior ovary, or the flower is said to be epigynous. Cross section of Tulip ovary In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the base of the petals and sepals.
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Fertile cavities, the conceptacles, containing the reproductive cells are immersed in the receptacles near the ends of the branches. After meiosis oogonia and antheridia, the female and male reproductive organs, produce egg cells and sperm respectively that are released into the sea where fertilisation takes place. The resulting zygote develops directly into the diploid plant. This contrasts with the life cycle of the flowering plant, where the egg cells and sperm are produced by a haploid multicellular generation, albeit very strongly reduced, and the egg cells are fertilised within the ovules of the parent plant and then released as seeds.
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Most are evergreen with the leaves persisting 2–10 years, but three genera (Glyptostrobus, Metasequoia and Taxodium) are deciduous or include deciduous species. Tetraclinis cones The seed cones are either woody, leathery, or (in Juniperus) berry-like and fleshy, with one to several ovules per scale. The bract scale and ovuliferous scale are fused together except at the apex, where the bract scale is often visible as a short spine (often called an umbo) on the ovuliferous scale. As with the foliage, the cone scales are arranged spirally, decussate (opposite) or whorled, depending on the genus.
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Lagenostoma is a genus of seed ferns (Pteridospermatophyta), based on ovules preserved in coal balls from the Six Inch Coal of the Hough Hill Colliery near Stalybridge, England. Distinctive stalked glands enabled Oliver and Scott to attribute these seeds to fernlike foliage of Sphenopteris hoeningshauseni in the same coal balls. This was the first recognition that some Carboniferous fernlike leaves had seeds, and so were not pteridophytes, but rather Pteridospermatophyta, or seed ferns. The realization that seed plants as well as spore plants had fernlike leaves was a major contribution to the evolutionary history of plants.
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One well studied plant species with diphasic sex expression is Arisaema Triphyllum, commonly known as Jack-in-the- pulpit. It is hypothesized that diphasic plant species have higher fitness when expressing only one sex at a time when there are trade-offs between size and reproductive success through male and female function. Due to conflict between male and female function when pollen and ovules are produced in the same flower, one sex is ultimately favored over the other dependent on plant size. This sex trade-off is responsible for determining the population sex ratio, meaning the relative amount of male versus female individuals.
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The holes provide a habitat for giant damselflies and other insects both when alive and once the tree has died and fallen over. It has compound leaves each of which is made up of 10–20 leaflets. Three new chemical compounds have been isolated from the leaves and they form part of the diet of several monkeys and the squirrel Sciurus ingrami. In Panama it flowers from April to June, the flowers contain only four ovules, but normally only one of these reaches maturity forming a winged seed pod around 10 cm long and weighing 2 g.
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It is also likely that post- transcriptional regulation exists, which controls its A function, or even that it has other purposes in the determination of organ identity independent of that mentioned here. In Antirrhinum, the orthologous gene to AP1 is SQUAMOSA (SQUA), which also has a particular impact on the floral meristem. The homologs for AP2 are LIPLESS1 (LIP1) and LIPLESS2 (LIP2), which have a redundant function and are of special interest in the development of sepals, petals and ovules. A total of three genes have been isolated from Petunia hybrida that are similar to AP2: P. hybrida APETALA2A (PhAP2A), PhAP2B and PhAP2C.
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This work led to the establishment of techniques of culture of young ovules and ovaries. This technique has also been used as an additional tool for obtaining improved varieties of rice, wheat, potato and other crops. She has also worked on regeneration of plants and mechanism of regeneration involving various enzymes, membrane phospholipids and second messengers during her time at the School of Life Sciences, Jawaharlal Nehru University, Delhi. Guha-Mukherjee then went to the US in late 1966 and worked with R. S. Bandurski at the Department of Botany and Plant Pathology as a research associate at Michigan State University.
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The modern framework for classification of the genera within Proteaceae was laid by L. A. S. Johnson and Barbara Briggs in their influential 1975 monograph "On the Proteaceae: the evolution and classification of a southern family". Their classification has been refined somewhat over the ensuing three decades, mot notably by Peter Weston and Nigel Barker in 2006, who included in Proteoideae the monophyletic Eidotheoideae, but separated from it two genera as the new Symphionematoideae. Proteaceae is now divided into five subfamilies, of which Proteoideae is the second largest. It is defined as those species having cluster roots, solitary ovules and indehiscent fruits.
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329x329px Young cones of a Blue Spruce The members of the pine family (pines, spruces, firs, cedars, larches, etc.) have cones that are imbricate (that is, with scales overlapping each other like fish scales). These pine cones, especially the woody female cones, are considered the "archetypal" tree cones. The female cone has two types of scale: the bract scales, and the seed scales (or ovuliferous scales), one subtended by each bract scale, derived from a highly modified branchlet. On the upper-side base of each seed scale are two ovules that develop into seeds after fertilization by pollen grains.
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The flowers may have four or five faintly connate but imbricate sepals with an equal number of distinct, imbricate petals. Also, the stamens, that may contain nectar discs, have distinct glabrous filaments that occur in one or two whorls and in numbers equaling or twice the number of petals; the tricolporate pollen is contained within two locules of the anthers that open longitudinally along slits. The gynoecium contains 3–5 connate carpels, one style, and one stigma that is head-like to lobed. Each locule of the superior ovary has two ovules with axile placentation that are anatropous to campylotropous.
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Geobiology, 3: 13-31.. The increase in abundance of the callistophytes coincided with a decline in abundance and diversity of the Lyginopteridales, which occupied very similar ecological niches and were very similar in general habit. It seems possible, therefore, that the reproductively more sophisticated callistophytes were able to out-compete and replace the Lyginopteridales. The Callistophytaceae flourished in Euramerica through Late Pennsylvanian times, eventually becoming extinct as this part of Pangaea became arid at the start of Permian times. They extend through the Permian of China and include anatomically preserved ovules of Callospermarion,Hilton, J., Wang S. J., Zhu W. Q., Tian B., Galtier, J. and Wei A. H. (2002).
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The evolutionary emergence of single-ovulated ovaries in plants has eliminated the need for a developing seed to compete for nutrients, thus increasing its chance of survival and germination. Likewise, the fathering of all ovules in multi-ovulated ovaries by one father, decreases the likelihood of competition between developing seeds, thereby also increasing the seeds' chances of survival and germination. The decreased root growth in plants grown with kin increases the amount of energy available for reproduction; plants grown with kin produced more seeds than those grown with non-kin. Similarly, the increase in light made available by alternating heights in groups of related plants is associated with higher fecundity.
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Reproductive isolation between species appears, in certain cases, a long time after fertilization and the formation of the zygote, as happens – for example – in the twin species Drosophila pavani and D. gaucha. The hybrids between both species are not sterile, in the sense that they produce viable gametes, ovules and spermatozoa. However, they cannot produce offspring as the sperm of the hybrid male do not survive in the semen receptors of the females, be they hybrids or from the parent lines. In the same way, the sperm of the males of the two parent species do not survive in the reproductive tract of the hybrid female.
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Conflict over seed size arises because there usually exists an inverse exponential relationship between seed size and fitness, that is, the fitness of a seed increases at a diminishing rate with resource investment but the fitness of the maternal parent has an optimum, as demonstrated by Smith and Fretwell (see also marginal value theorem). However, the optimum resource investment from the offspring's point of view would be the maximum that it can possibly get from the maternal parent. This conflict about resource allocation is most obviously manifested in the reduction of brood size (i.e. a decrease in the proportion of ovules matured into seeds).
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The descriptive term "petaloid lilioid monocot" relates to the conspicuous petal-like (petaloid) tepals which superficially resemble true lilies (Lilium). Morphologically, the petaloid or lilioid monocots can be considered to possess five groups (pentacyclic) of three-fold (trimerous) whorls. Lilioid monocots all have flowers which can be considered to have been derived from a lily-like flower with six relatively similar tepals, and six stamens. The typical lilioid gynoecium has three carpels fused into a superior trilocular (three- chambered) superior ovary, axile placentation, a single hollow style, and several ovules with anatropous orientation in one or two rows per locule and nectaries at the base.
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For some varieties, such as Zinfandel and Merlot, flowering may be more staggered which poses a greater risk for inclemental weather disrupting the process and encouraging millerandage. Some growers may try to encourage more synchronized flowering with the use of chemical treatments, such as cyanamide.R. Jackson "Wine Science: Principles and Applications" Third Edition pgs 70-72 Academic Press 2008 Following flowering, the flowers of the grape vine go through pollination and fertilization over the next 2 to 3 days. Here is another opportunity where incremental weather can influence the outcome with temperature drops below potentially damaging the ovules of the flowers before they can be fertilized.
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Cycas sp. The earliest fossils of the genus Cycas appear in the Cenozoic although Cycas-like fossils that may belong to Cycadaceae extend well into the Mesozoic. Cycas is not closely related to other genera of cycads, and phylogenetic studies have shown that Cycadaceae is the sister-group to all other extant cycads. Cycas is thought to retain a number of ancestral characters that have been modified in the other cycads (Stangeriaceae and Zamiaceae): in particular, the ovulate ('female') cone has very large ovules attached to megasporophylls that are held in a lax rosette rather than in the tight cone found in other cycads.
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The superior ovary in the center of the flower consists of three merged carpels, that together protect three cavities within which are one to four anatropous ovules each of which is covered by a single layer. The upright style tapers towards the top and carries a small globe-shaped stigma or expands towards the top into an inverted cone-shaped stigma, covered in small grains. The smooth, cartilaginous, dehiscent fruit opens with three valves. The small, dark reddish brown seeds are ellipsoid in shape either with a smoothed netted structure or angular with three sutures and with prominent warts or a honeycomb-like structure.
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Engler & Prantl favoured placing E. caudatum in Wulfhorstia because it has only 6 ovules in each loculus, and because it lacks partitions inside the staminal tube, the feature which struck Anne Casimir Pyrame de Candolle when he named it Entandrophragma in 1894. The partitions, though, are variable in species and are very short in Entandrophragma speciosa Harms, so that the differences between the two genera become trivial and untenable.Hooker’s Icones Plantarum, vol. 31 The fruit of this species is remarkable and when green has the form of a cigar- or club- shaped capsule some 40mm in diameter at the thick end and some 150mm in length.
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The pollen is usually monosulcate (single groove), but may be inaperturate (lacking aperture: Clintonia, some Tulipa spp.) or operculate (lidded: Fritillaria, some Tulipa spp.), and reticulate (net patterned: Erythronium, Fritillaria, Gagea, Lilium, Tulipa). ; Gynoecium : Superior ovary (hypogynous), syncarpous (with fused carpels), with three connate (fused) carpels and is trilocular (three locules, or chambers) or unilocular (single locule, as in Scoliopus and Medeola). There is a single style and a three lobed stigma or three stigmata more or less elongated along the style. There are numerous anatropous (curved) ovules which display axile placentation (parietal in Scoliopus and Medeola), usually with an integument and thinner megasporangium.
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The pedicel is 1 cm, green; the perianth has a short green tube, 5 mm, much shorter than the tepal segments, spreading in six white tepals, 15 mm long and 2.5 mm wide, linear-lanceolate, a bit broadened below the apex, gradually attenuate (narrowing) towards the base, subequal (nearly equal), keeled green on the abaxial surface, keel formed by 3 closely spaced veins. The stamens are biseriate, free, inserted at the throat, 3 equaling the tepals, 3 shorter; filaments filiform; anthers dorsifixed (attached to the filaments at their middle), oblong, versatile, yellow; style white, filiform, and terete. Stigma captitate, obscurely 3-lobed. Ovary with 3 locules; ovules 5-6 per locule.
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The framework for classification of genera within Proteaceae was laid by L. A. S. Johnson and Barbara Briggs in their influential 1975 monograph "On the Proteaceae: the evolution and classification of a southern family". Their arrangement has been refined somewhat over the ensuing three decades, most notably by Peter H. Weston and Nigel Barker in 2006. Proteaceae is divided into five subfamilies, with Adenanthos placed in subfamily Proteoideae because of its cluster roots, solitary ovules and indehiscent fruits. On the basis of phylogenetic data it is further placed in tribe Leucodendreae, a morphologically heterogeneous group with no obvious diagnostic characters, and dominated by South African genera.
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Based on the elongated rostrum, antennae, and ovipositor structures; species in mesophyletidae were likely specialized herbivores which predated seeds and plant ovules in manners similar to that of the living Anthonomini, Curculionini, and related curculionid tribes. The legs are modified with elongated tarsi sporting large claws and tibia with strengthening ridges and a flattened or flared profile. These adaptations indicate an arboreal life of climbing on smooth or flimsy plant organs such as leaves and fruits. Additionally the elytra did not lock along the tips, and are loose to the pygidium which would allow for quick transition to flight, something the group was likely proficient at.
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In 1983, research horticulturist David W. Ramming and technician Ronald L. Tarailo—Californian grape breeders working for the ARS, the chief scientific research agency of the USDA—crossed Thompson Seedless and Concord in order to answer a technical question about a newly developed procedure for breeding novel, superior seedless grapes. The researchers wanted to demonstrate that plants created from embryo culture were derived from fertilized eggs (zygotic) instead of the maternal tissue (somatic). From 1231 emasculations (removal of male flower parts to control pollination) of Thompson Seedless, the researchers produced 130 ovules using embryo rescue procedures. From these, 40 embryos developed and three seedlings were planted.
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Cycas beddomei is a species of cycad in the genus Cycas, native to India, where it is confined to a small area of Andhra Pradesh state in the Tirumala Hills in scrubland and brush covered hills. Superficially similar to Cycas revoluta, it has erect, solitary stems. There are 20-30 leaves in the crown, each leaf 90 cm long, stiff, lanceolate, pinnate, with 50-100 pairs of leaflets, these 10-17.5 cm long and 3–4 mm wide, and angled forward at 45 degrees; the leaf petiole bears minute spines. The female cones are open, with sporophylls 15–20 cm long, with pink-brown coloured tomentose down, with two ovules.
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A lesser violetear Inflorescences of Butea allow birds to perch on the stalk Plant adaptations for ornithophily can be grouped primarily into those that attract and facilitate pollen transfer by birds, and those that exclude other groups, primarily insects, protecting against 'theft' of nectar and pollen. The ovules of bird flowers also tend to have adaptations that protect them from damage during vigorous foraging by hard bird bills. The flowers of generalist bird-pollinated plant species differ from those pollinated by specialized birds, such as hummingbirds or sunbirds by lacking long corolla tubes and having brush-like, exserted stamens. Most bird pollinated flowers are red and have a lot of nectar.
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The ovary is linear, 1–1½ cm (0.4–0.6 in) long, towards the tip with four to six grooves and ridges, and four to six compartments, in each of which are two rows of ovules attached to the axis at the centre. The stigma at the top is seated and indistinct. The fruit is on a long stalk above the scars of the stamens, and is a drooping, knobbly, angular cylindrical capsule, of long and in diameter, with a long beak at the tip. When ripe, the walls of the fruits are shed in longitudinal strips starting from the base, showing the axis with eight to twelve rows of large, initially red, later red-brown kidney-shaped seeds.
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For pollination to occur, pollen grains must attach to the stigma of the female reproductive structure (carpel), where the female gametophytes (ovules) are located inside the ovary. After the pollen tube grows through the carpel's style, the sex cell nuclei from the pollen grain migrate into the ovule to fertilize the egg cell and endosperm nuclei within the female gametophyte in a process termed double fertilization. The resulting zygote develops into an embryo, while the triploid endosperm (one sperm cell plus two female cells) and female tissues of the ovule give rise to the surrounding tissues in the developing seed. The ovary, which produced the female gametophyte(s), then grows into a fruit, which surrounds the seed(s).
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Sarcomelicope is a genus of about ten species flowering plants in family Rutaceae endemic to the South Pacific. Plants in the genus Sarcomelicope are shrubs to medium-sized trees with simple leaves and flowers arranged in panicles in leaf axils, separate male and female flowers with four sepals and four petals that are free from each other and overlapping at the base. Male flowers have eight stamens that are free from each other and female flowers have four carpels that are fused, at least at the base with two ovules in each carpel. The fruit is a drupe of four carpels, partly or completely fused, and the seeds are dark brown to black.
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Grahamia australiana is a perennial succulent herb with weak, fleshy branches which have succulent, sessile leaves arranged alternately around their tips and which has tuberous roots and ascending flowering stems up to 20 cm in length which are leafy towards their base. The leaves are oblanceolate to obovate in shape, and are infrequently elliptic, measuring 1–2.5 cm in length and 5–12 mm across with a sharp point at the tip and covered in hairs. The inflorescences consist of few-flowered cymes The sepals enclose the 5 white to pinkish petals which are each 5–15 mm long and there are 8-10 stamens. The superior ovary is round and contains numerous ovules.
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Two of the three yucca moth genera in particular, Tegeticula and Parategeticula, have an obligate pollination mutualism with yuccas. Yuccas are only pollinated by these moths, and the pollinator larvae feed exclusively on yucca seeds; the female moths use their modified mouthparts to insert the pollen into the stigma of the flowers, after having oviposited in the ovary, where the larvae feed on some (but not all) of the developing ovules. This obligate pollination mutualism is similar to the mutualistic relationship between the senita cactus and the senita moth. Species of the third genus of yucca moths, Prodoxus, are not engaged in the pollination mutualism, nor do the larvae feed on developing seeds.
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Some are andromonoecious, polygamomonoecious, or even dioecious (as in Acronema), with a distinct calyx and corolla, but the calyx is often highly reduced, to the point of being undetectable in many species, while the corolla can be white, yellow, pink or purple. The flowers are nearly perfectly pentamerous, with five petals, sepals, and stamens. The androecium consists of five stamens, but there is often variation in the functionality of the stamens even within a single inflorescence. Some flowers are functionally staminate (where a pistil may be present but has no ovules capable of being fertilized) while others are functionally pistillate (where stamens are present but their anthers do not produce viable pollen).
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Liverwort species are either dioecious (dioicous) as shown here or monoecious (monoicous), with both antheridia and archegonia on the same gametophyte Land plants have alternation of generations, for which the sporophyte generation produces spores rather than gametes. Strictly speaking, the sporophytes of land plants do not have either male or female reproductive organs. The gametophytes of flowering plants are of a single sex; the male gametophytes are contained within the pollen, and the female gametophytes are contained within ovules. The sporophyte generation is called dioecious when each sporophyte has only one kind of spore-producing organ whose spores ultimately give rise to either all male gametes (sperm) or all female gametes (eggs).
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Plants exhibiting selfing syndrome are typically autogamous and display reduced pollen ovule (P/O) ratios, resulting in a smaller pollen count and a larger number of ovules. The reduction of flower size has been studied between the selfing species Capsella rubella and its closely related outcrossing relative Capsella grandiflora. The petals between the two species grow at the same rate, however, a decrease in the sterile apetela (SAP) protein activity due to variation in the SAP intron in C. rubella is responsible for reduced petal size. This is due to the smaller number of cells present in the petal and results in petals that are around 35% smaller than the petals of C. grandiflora.
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Delayed Selfing – A mechanism providing reproductive assurance at a lower cost than autonomous selfing, when the anthers or stigma change position as the flower ages, bringing them into close proximity and promoting self- pollination. Reproductive Compensation – A result of more ovules than can mature into seeds, and the production of large numbers of seeds over the lifespan of a perennial plant, can contribute to the evolution of mixed mating systems. Rare selfed seedlings with higher fitness may decrease the fitness difference between selfed and out-crossed offspring. Cleistogamy – Most plants producing cleistogamous (closed, selfing) flowers also produce chasmogamous (open, outcrossing) flowers, and consequently will typically produce mixtures of selfed and out-crossed seeds.
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Diagram showing the sexual parts of a mature flower It was Rudolf Camerarius (1665–1721) who was the first to establish plant sexuality conclusively by experiment. He declared in a letter to a colleague dated 1694 and titled ' that "no ovules of plants could ever develop into seeds from the female style and ovary without first being prepared by the pollen from the stamens, the male sexual organs of the plant". Much was learned about plant sexuality by unravelling the reproductive mechanisms of mosses, liverworts and algae. In his ' of 1851 Wilhelm Hofmeister (1824–1877) starting with the ferns and bryophytes demonstrated that the process of sexual reproduction in plants entails an "alternation of generations" between sporophytes and gametophytes.
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The pistil is the female reproductive organ of a flower that is composed of an ovary and several free carpels the style and the stigma. A carpel is the modified leaf that contains the ovules and has a style and a stigma on top. The style is the stalk-like portion that connects the stigma and the carpel or ovary; whereas the stigma, itself, is the top most receptive region of the style, commonly divided. In Pachypodium baronii the pistil is 12.5 mm (0.49-inch) to 14.5 mm (0.57-inch) long. The ovary measures 2 mm (0.078-inch) to 2.5 mm (0.098-inch) long by 1.8 mm (0.071-inch) to 2.2 mm (0.87-inch) wide by 1.5 mm (0.059-inch) high.
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However, as opposed to 'complete' or 'absolute' SI, in CSI, self-pollination without the presence of competing cross pollen, results in successive fertilization and seed set; in this way, reproduction is assured, even in the absence of cross-pollination. CSI acts, at least in some species, at the stage of pollen tube elongation, and leads to faster elongation of cross pollen tubes, relative to self pollen tubes. The cellular and molecular mechanisms of CSI have not been described. The strength of a CSI response can be defined, as the ratio of crossed to selfed ovules, formed when equal amounts of cross and self pollen, are placed upon the stigma; in the taxa described up to this day, this ratio ranges between 3.2 and 11.5.
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Seedless fruits can develop in one of two ways: either the fruit develops without fertilization (parthenocarpy), or pollination triggers fruit development, but the ovules or embryos abort without producing mature seeds (stenospermocarpy). Seedless banana and watermelon fruits are produced on triploid plants, whose three sets of chromosomes make it very unlikely for meiosis to successfully produce spores and gametophytes. This is because one of the three copies of each chromosome can't pair with another appropriate chromosome before separating into daughter cells, so these extra third copies end up randomly distributed between the two daughter cells from meiosis 1, resulting in the (usually) swiftly lethal aneuploidy condition. Such plants can arise by spontaneous mutation or by hybridization between diploid and tetraploid individuals of the same or different species.
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Function D specifies the identity of the ovule, as a separate reproductive function from the development of the carpels, which occurs after their determination. Function E relates to a physiological requirement that is a characteristic of all floral verticils, although, it was initially described as necessary for the development of the three innermost verticils (Function E sensu stricto). However, its broader definition (sensu lato) suggests that it is required in the four verticils. Therefore, when Function D is lost the structure of the ovules becomes similar to that of leaves and when Function E is lost sensu stricto, the floral organs of the three outer most verticils are transformed into sepals, while on losing Function E sensu lato, all the verticils are similar to leaves.
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One major impediment to breeding bananas is polyploidy; Gros Michel and Cavendish bananas are triploid and thus attempts at meiosis in the plant's ovules cannot produce a viable gamete. Only rarely does the first reduction division in meiosis in the plants' flowers tidily fail completely, resulting in a euploid triploid ovule, which can be fertilized by normal haploid pollen from a diploid banana variety; a whole stem of bananas would contain only a few seeds and sometimes none. As a result, the resulting new banana variety is tetraploid, and thus contains seeds; the market for bananas is not accustomed to bananas with seeds. Experience showed that where both meiosis steps failed, causing a heptaploid seedling, or when the seedling is aneuploid, results are not as good.
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The calyx is greatly reduced or nonexistent in most species and the petals are joined together at the tip into one unit but separated at the base. The fruit is a berry, ovoid in shape and juicy, with a two-celled ovary each containing two ovules, thus normally producing four seeds per flower (or fewer by way of aborted embryos).Gleason and Cronquist volume 2, New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada, p. 517. Other parts of the vine include the tendrils which are leaf-opposed, branched in Vitis vinifera, and are used to support the climbing plant by twining onto surrounding structures such as branches or the trellising of a vine-training system.
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Androgynous inflorescences usually with female flowers at proximal nodes and male flower at distal nodes. Flowers unisexual, apetalous, disc absent. Male flowers very small, shortly pedicellate, globose in bud; calyx parted into 4 small valvate sepals; stamens 4–8(–16) on a slightly raised receptacle, filaments free or basally connate; anthers with divaricate or pendulous thecae, unilocular, more or less elongated and later becoming vermiform; pollen grains oblate-spheroidal, with 3–5 pseudopores, tectate, psilate; pistillode absent. Female flowers generally sessile or subsessile, pedicellate in a few species; calyx of 3– (4–5) small sepals imbricate, connate at base; ovary of [1–2]3 carpels, surface often muricate, pubescent or papillose; ovules solitary in each cell, anatropes; styles reddish, free or basally connate, several times divided into filiform segment, rarely bifid or entire; staminodes absent.
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Ovule structure (anatropous) 1: nucleus 2: chalaza 3: funiculus 4: raphe Ovule orientation may be anatropous, such that when inverted the micropyle faces the placenta (this is the most common ovule orientation in flowering plants), amphitropous, campylotropous, or orthotropous (anatropous are common and micropyle is in downward position and chalazal end in on the upper position hence, in amphitropous the anatropous arrangement is tilted 90 degrees and in orthotropus it is completely inverted) . The ovule appears to be a megasporangium with integuments surrounding it. Ovules are initially composed of diploid maternal tissue, which includes a megasporocyte (a cell that will undergo meiosis to produce megaspores). Megaspores remain inside the ovule and divide by mitosis to produce the haploid female gametophyte or megagametophyte, which also remains inside the ovule.
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This can be seen in Cannabis sativa, a type of hemp, which have higher photosynthesis rates in males while growing but higher rates in females once the plants become sexually mature. p. 206 Every sexually reproducing extant species of vascular plant actually has an alternation of generations; the plants we see about us generally are diploid sporophytes, but their offspring really are not the seeds that people commonly recognise as the new generation. The seed actually is the offspring of the haploid generation of microgametophytes (pollen) and megagametophytes (the embryo sacs in the ovules). Each pollen grain accordingly may be seen as a male plant in its own right; it produces a sperm cell and is dramatically different from the female plant, the megagametophyte that produces the female gamete.
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Magnolia × wieseneri showing the many pistils making up the gynoecium in the middle of the flower Hippeastrum flowers showing stamens, style and stigma Hippeastrum stigmas and style Moss plants with gynoecia, clusters of archegonia at the apex of each shoot. Gynoecium (, from Ancient Greek , gyne, meaning woman, and , oikos, meaning house) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) pistils and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e.
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Although many factors may contribute to determining ovule number, one way for females to increase the level of pollen competition is to decrease ovule number while maintaining stigma size. The evolution of functional syncarpy (assuming no other attendant changes) presumably is a simultaneous increase in the number of ovules accessible from one stigma, which tended to decrease the intensity of pollen competition, and a concentration of pollen deposition on a single stigma, which tends to increase pollen competition. Further increases in pollen competition could be brought about by an increase in pollen delivery (through change of pollinator, increased attractiveness of floral display, or rewards), a decrease in ovule number or stigma size, changes in temporal patterns of stigma receptivity, or changes in the competitive environment of the carpel .
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Some palaeobotanists also included seed plant groups with entire leaves such as the Glossopteridales and Gigantopteridales, which was stretching the concept. In the context of modern phylogenetic models, the groups often referred to as pteridosperms appear to be liberally spread across a range of clades, and many palaeobotanists today would regard pteridosperms as little more than a paraphyletic 'grade-group' with no common lineage. One of the few characters that may unify the group is that the ovules were borne in a cupule, a group of enclosing branches, but this has not been confirmed for all "pteridosperm" groups. With regard to the enduring value of the division, many palaeobotanists still use the pteridosperm grouping in an informal sense to refer to the seed plants that are not angiosperms, coniferoids (conifers or cordaites), ginkgophytes or cycadophytes (cycads or bennettites).
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Distyly is a type of heterostyly in which a plant demonstrates reciprocal herkogamy. This breeding system is characterized by two separate flower morphs, where individual plants produce flowers that either have long styles and short stamens (traditionally referred to as “pin”, modern nomenclature refers to them as the “long-morph” or "L-morph" flowers), or that have short styles and long stamens (traditionally referred to as “thrum”, modern nomenclature refers to these as the “short-morph” or "S-morph" flowers). However, distyly can refer to any plant that has two morphs if at least one of the following characteristics between flowers produced by different plants is true; there is a difference in style length, filament length, pollen size or shape, or the surface of the stigma. Most distylous plants are self- incompatible so they cannot fertilize ovules in their own flowers.
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The corolla is ochroleucous (whitish), tinged or veined with dull lilac or purple; banner 4¾–6 mm, moderately recurved (45–85°); wings nearly as long; very obtuse keel, 3½–4 mm. The pods are small, sessile, puberulent to strigose, spreading to declined, often humistrate, in profile ovoid-oblong, straight or a trifle incurved, obtuse at base, abruptly acute at apex to short-mucronate, thickened, incompletely to fully bilocular (2-celled), cordate in cross-section, trigonous or compressed-triquetrous, the lateral faces flat, the dorsal (upper or adaxial) face narrower and sulcate (grooved), carinate by the ventral suture, the dorsal suture shallowly to deeply sulcate; thin, papery, green to stramineous (brownish) valves strigulose, 4–7 mm long, 1½ -2½ mm in diameter, deciduous from receptacle, dehiscence primarily basal and occurs after falling. The ovary is strigulose and contains a few seeds (ovules 4–8).
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It is a perennial deciduous shrub that grows in grows in open areas , forests, arrow bamboo grove, or cuttings with good light transmission. The plant height is about 1 meter and there are three small thorns on the stem. Leaves 8–10 together, papery narrowly obovate to oblanceolate, leaf about 1.5–2.5 cm in length, and 0.5–1 cm in width. The leaf margins are sparsely sharply serrate, and the leaves on both sides are of the same color and hairless, but sometimes the lower half of the leaves will be pale green with obvious veins. Yellow long elliptic flowers, 3-6 bunches clustered in leaf axils, short panicles; pedicels 2.5-3 cm long; outer sepals long-ovate, about 3.5 cm long, 1.5 cm wide, and inner sepals 6 cm long , 3 cm wide; petals are elliptic, 5-6 cm long, 3-3.5 cm wide; ovules approximately 4-9.
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Fluffy flowers of Tetradenia riparia (misty plume bush) Flowers of Malus sylvestris (crab apple) Flowers and leaves of Senecio angulatus (creeping groundsel) Two bees on the composite flower head of creeping thistle, Cirsium arvense Based on current evidence, some propose that the ancestors of the angiosperms diverged from an unknown group of gymnosperms in the Triassic period (245–202 million years ago). Fossil angiosperm-like pollen from the Middle Triassic (247.2–242.0 Ma) suggests an older date for their origin. A close relationship between angiosperms and gnetophytes, proposed on the basis of morphological evidence, has more recently been disputed on the basis of molecular evidence that suggest gnetophytes are instead more closely related to other gymnosperms. The fossil plant species Nanjinganthus dendrostyla from Early Jurassic China seems to share many exclusively angiosperm features, such as a thickened receptacle with ovules, and thus might represent a crown-group or a stem-group angiosperm.
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The plants are annual or perennial, growing emersed, floating-leaved, or seasonally submersed, leaves glabrous to stellate-pubescent; rhizomes present or absent; stolons absent; corms absent; tubers absent. Roots not septate. Leaves sessile or petiolate; petioles triangular, rarely terete; blade with translucent markings as dots or lines present or absent, linear to lanceolate to ovate, base attenuate to cordate, margins entire or undulating, apex obtuse to acute. Inflorescences racemes or panicles, rarely umbels, of 1-18 whorls, erect or decumbent, emersed; bracts coarse, apex obtuse to acute, surfaces smooth or papillose along veins, apex obtuse to acute. Flowers bisexual, subsessile to pedicellate; bracts subtending pedicels, subulate to lanceolate, shorter than to longer than pedicels, apex obtuse to acute; pedicels ascending to recurved; receptacle convex; sepals recurved to spreading, herbaceous to leathery, sculpturing absent; petals white, entire; stamens 9-25; filaments linear, glabrous; pistils 15-250 or more, spirally arranged on convex receptacle, forming head, distinct; ovules 1; style terminal or lateral.
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Travelling between the sexes, the weevils pollinate the plants by inadvertently transferring pollen from the male cones to the receptive ovules of the female cones. Threats to the species includes the construction of a small hydro electric power plant on the Mpanga River Falls, the construction of roads and camps in the cycad belt, causing soil erosion and deep gullies, reducing habitat quality, the reduction in population of mature and young individuals as they are knocked down by heavy machinery and reduction in area of occupancy owing to parts being occupied by weir (reservoir), water canal, and power house. Moreover, it is reported that the collection of seed and seedlings for commercial trade may impair the regeneration capacity of the cycad and thus lead to further reduction of its population. Other threats are the cultivation on the slopes of the gorge and clearing of the cycads, harvesting of the cycad leaves for building materials, burning of some areas occupied by the cycad for stimulation of grazing pasture.
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The genus was named in 1868 by Ferdinand von Mueller in honour of Richard Grenville, the Duke of Buckingham, who was Secretary of State for the Colonies from 1866 to 1868. It was initially placed in a tribe Grevilleae, but the feature of having four ovules per carpel led C. Venkata Rao to classify it in the tribe Telopeae, and within this a new subtribe Hollandaeae based on the antero-posterior orientation of the perianth, with the genera Hollandaea, Cardwellia, Knightia, Opisthiolepis and Stenocarpus. Lawrie Johnson and Barbara G. Briggs recognised the affinities of this genus with the rainforest taxon Opisthiolepis and classified the two in the subtribe Buckinghamiinae within the tribe Embothrieae in the subfamily Grevilleoideae in their 1975 monograph "On the Proteaceae: the evolution and classification of a southern family", and thus related to Lomatia, Stenocarpus and the Embothriinae. However, analysis of chloroplast sequences revealed a much closer relationship of Buckinghamia and Opisthiolepis with Grevillea instead.
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The pollen grains are dispersed by the wind to the female, ovulate cone that is made up of many overlapping scales (sporophylls, and thus megasporophylls), each protecting two ovules, each of which consists of a megasporangium (the nucellus) wrapped in two layers of tissue, the integument and the cupule, that were derived from highly modified branches of ancestral gymnosperms. When a pollen grain lands close enough to the tip of an ovule, it is drawn in through the micropyle ( a pore in the integuments covering the tip of the ovule) often by means of a drop of liquid known as a pollination drop. The pollen enters a pollen chamber close to the nucellus, and there it may wait for a year before it germinates and forms a pollen tube that grows through the wall of the megasporangium (=nucellus) where fertilisation takes place. During this time, the megaspore mother cell divides by meiosis to form four haploid cells, three of which degenerate.
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In A. thaliana, function A is mainly represented by two genes APETALA1 (AP1) and APETALA2 (AP2) AP1 is a MADS-box type gene, while AP2 belongs to the family of genes that contains AP2, which it gives its name to and which consists of transcription factors that are only found in plants. AP2 has also been shown to complex with the co-repressor TOPLESS (TPL) in developing floral buds to repress the C-class gene AGAMOUS (AG). However, AP2 is not expressed in the shoot apical meristem (SAM), which contains the latent stem cell population throughout the adult life of Arabidopsis, and so it is speculated that TPL works with some other A-class gene in the SAM to repress AG.AP1 functions as a type A gene, both in controlling the identity of sepals and petals, and it also acts in the floral meristem. AP2 not only functions in the first two verticils, but also in the remaining two, in developing ovules and even in leaves.
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Character and description of Kingia was first published in 1826 as an appendix to the second volume of Phillip Parker King's Narrative of a survey of the intertropical and western coasts of Australia performed between the years 1818 and 1822. Character and description of Kingia, a new genus of plants found on the south-west coast of New Holland, with observations on the structure of its unimpregnated ovulum, and on the female flower of Cycadeae and Coniferae is an 1826 paper by botanist Robert Brown. Though nominally a formal description of the then-unpublished genus Kingia, it is more notable for its digressions into ovule anatomy and development, in which Brown sets out for the first time the modern understanding of the structure of angiosperm ovules, and publishes the first description of the fundamental difference between angiosperms and gymnosperms. Of the latter it has been said that "no more important discovery was ever made in the domain of comparative morphology and systematic Botany".
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There has been documentation of the symbiotic relationship the Guamanian C. micronesica with Anatrachyntis sp., which depends on male cones (microsporangia) for oviposition and recruitment in return for pollinating the species. Fertilized megasporangia with developing seeds. Image by Lauren Gutierrez. The microsporangiate cones are pale fawn to pale orange- brown, narrowly ovoid, 30–50 cm long, 8–10 cm in diameter. Microsporophyll lamina are 35–45 mm long, 20–25 mm wide; fertile zone 25–35 mm long; sterile apex 7–10 mm long, not recurved, apical spine somewhat reduced, broad, sharply upturned, 2 mm long. Megasporophylls 27–33 cm long, grey- and orange- tomentose, with 2-6 ovules, lamina 45–55 mm wide, broadly ovate to elliptical, regularly dentate with 16-20 lateral spines, apical spine 8–15 mm long, lateral spines 2–6 mm long. Seeds flatten to ovoid, green becoming orange, not pruinose, 50–60 mm long, 45–50 mm in diameter; sarcotesta 3–6 mm thick.
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Lack's principle implies that birds that happen to lay more eggs than the optimum will most likely have fewer fledglings (young that successfully fly from the nest) because the parent birds will be unable to collect enough food for them all. Evolutionary biologist George C. Williams notes that the argument applies also to organisms other than birds, both animals and plants, giving the example of the production of ovules by seed plants as an equivalent case. Williams formalised the argument to create a mathematical theory of evolutionary decision-making, based on the framework outlined in 1930 by R. A. Fisher, namely that the effort spent on reproduction must be worth the cost, compared to the long-term reproductive fitness of the individual. Williams noted that this would contribute to the discussion on whether (as Lack argued) an organism's reproductive processes are tuned to serve its own reproductive interest (natural selection), or as V.C. Wynne-Edwards proposed, to increase the chances of survival of the species to which the individual belonged (group selection).
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Gloriosa are herbaceous perennials that climb or scramble over other plants with the aid of tendrils at the ends of their leaves and can reach 3 meters in height. They have showy flowers, many with distinctive and pronouncedly reflexed petals, like a Turk's cap lily, ranging in colour from a greenish-yellow through yellow, orange, red and sometimes even a deep pinkish-red. "Scandent herbs, the rootstock a horizontal rhizome, the stem leafy, the leaves spirally arranged or subopposite, the upper ones with cirrhose tips; flowers solitary, large, borne on long, spreading pedicels, actinomorphic, hermaphrodite; perianth segments 6, free, lanceolate, keeled within at base, long-persistent; stamens 6, hypogynous, the anthers extrorse, medifixed and versatile, opening by longitudinal slits; ovary superior, 3-celled, the carpels cohering only by their inner margins, the ovules numerous, the style deflected at base and projecting from the flower more or less horizontally; fruit a loculicidal capsule with many seeds"Smith, Albert C. 1979. Flora Vitiensis nova: A new flora of Fiji (Spermatophytes only).
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