Fossils collected in May 2001 include possible first finds of the sphenopsid Equisetites, and an undescribed cycadeoid reproductive structure.
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The haloid gametophyte generation is the dominant state. Begins with the haploid spores that gives rise to protonema, and eventually producing the gametophyte. The gametophyte then develops the reproductive structures: archegonium, the female reproductive structure that produces eggs, and antheridium, the male reproductive structure that produces sperms. The egg and the sperm fuse together to form a diploid zygote.
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In the mosses and liverworts (Marchantiophyta), the perianth is the sterile tubelike tissue that surrounds the female reproductive structure (or developing sporophyte).
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There are several alternatives to dioecy for sexual reproductive structure organization in plants including bisexual flowers, monoecy, gynomonoecy, andromonoecy. These are described at Plant reproductive morphology.
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The perichaetium is reproductive structure which holds the female organs. It is made up of an archegonia, paraphyses, and perichaetial leaves. The perichaetium is located on short axillary branches.
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The antheridium (plural: antheridia) is the reproductive structure found on a male bryophyte shoot. An antheridium has a jacket that protects the sperm while they are developing. Once the sperm has matured, the sperm requires water, such as raindrops, to help carry the sperm from an antheridium to an egg located in an archegonium on a female gametophyte shoot. The perigonium structure is composed of an antheridium, paraphyses (sterile filaments that support the reproductive structure of bryophytes), and perigonial leaves.
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The perigonium is the reproductive structure which holds the male organs. It is made up of an antheridia, paraphyses and perigonial leaves. Paraphyses are upright sterile filament-like structures that support the reproductive apparatus of bryophytes.
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Both can form abundant protoperithecia, the female reproductive structure (see figure, top of §). Protoperithecia are formed most readily in the laboratory when growth occurs on solid (agar) synthetic medium with a relatively low source of nitrogen. Nitrogen starvation appears to be necessary for expression of genes involved in sexual development.
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A synnema (plural synnemata, also coremia; derivation: "Threads together") is a large, erect reproductive structure borne by some fungi, bearing compact conidiophores, which fuse together to form a strand resembling a stalk of wheat, with conidia at the end or on the edges. Fungal genera which bear synnemata include Doratomyces.
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A columella (pl. columellae) is a sterile (non-reproductive) structure that extends into and supports the sporangium of some species. In fungi, the columella, which may be branched or unbranched, may be of fungal or host origin. Secotium species have a simple, unbranched columella, while in Gymnoglossum species, the columella is branched.
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Stylidium (also known as triggerplants or trigger plants) is a genus of dicotyledonous plants that belong to the family Stylidiaceae. The genus name Stylidium is derived from the Greek στύλος or stylos (column or pillar), which refers to the distinctive reproductive structure that its flowers possess.Curtis's Botanical Magazine. (1832). Stylidium scandens, Volume 59: Plate 3136.
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Papery (upper) and leafy bracts on hay rattle (Rhinanthus minor). All the "leaves" in this image are bracts. In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are often (but not always) different from foliage leaves.
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Scytothamnus australis has a unilocular sporangia reproductive structure which means that it can produce meiospores or asexual spores. The gametophytes are dioecious (Dioecy) but no structural difference can be detected between the gametangia of male and female isolates. In "Scytothamnus australis" the gametes vary considerably in size, ranging from 3-6 ~tm in diameter.
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Such arils are also found in a few species of gymnosperms, notably the yews and related conifers such as the lleuque and the kahikatea. Instead of the woody cone typical of most gymnosperms, the reproductive structure of the yew consists of a single seed that becomes surrounded by a fleshy, cup-like covering. This covering is derived from a highly modified cone scale.
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A herbarium specimen of the lichen Leptogium cyanescens, magnifed 40X, with lobule-shaped isidia. An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting of both fungal hyphae (the mycobiont) and algal cells (the photobiont).
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The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as cedar, celery-pine, cypress, fir, juniper, larch, pine, redwood, spruce, and yew, are included here. Some fossil conifers, however, belong to other distinct orders within the division Pinophyta.
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Flax root cortical cells containing paired arbuscules. Diagram of an apothecium (the typical cup-like reproductive structure of Ascomycetes) showing sterile tissues as well as developing and mature asci. Members of the Glomeromycota form arbuscular mycorrhizae, a form of mutualist symbiosis wherein fungal hyphae invade plant root cells and both species benefit from the resulting increased supply of nutrients. All known Glomeromycota species reproduce asexually.
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In some Basidiomycota the spores are not ballistic, and the sterigmata may be straight, reduced to stubbs, or absent. The basidiospores of these non-ballistosporic basidia may either bud off, or be released via dissolution or disintegration of the basidia. Scheme of a typical basidiocarp, the dipoid reproductive structure of a basidiomycete, showing fruiting body, hymenium and basidia. In summary, meiosis takes place in a diploid basidium.
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Geranium nodosum is a rhizomatous geophyte, a plant that propagates by means of a rhizome, a reproductive structure in the form of a horizontal stem which produces the stem and the roots below the soil surface. During the winter the plant has no aboveground herbage, having become reduced to the rhizome. The plant generally reaches in height, with a maximum of .Pignatti, S. Flora d'Italia – Edagricole. Vol.
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Historian Thomas W. Laqueur suggests that from the Renaissance to the 18th century, there was a prevailing inclination among doctors towards the existence of only one biological sex (the one-sex theory, that women and men had the same fundamental reproductive structure).Lacqueur, Thomas Walter, Making Sex: Body and Gender From the Greeks to Freud (Cambridge, Massachusetts: Harvard Univ. Press, 1st Harvard Univ. Press pbk. ed.
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Both can form abundant protoperithecia, the female reproductive structure (see Figure). Protoperithecia are formed most readily in the laboratory when growth occurs on solid (agar) synthetic medium with a relatively low source of nitrogen. Nitrogen starvation appears to be necessary for expression of genes involved in sexual development. The protoperithecium consists of an ascogonium, a coiled multicellular hypha that is enclosed in a knot-like aggregation of hyphae.
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A poster with flowers or clusters of flowers produced by twelve species of flowering plants from different families. Flowers in the Netherlands. A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism for the union of sperm with eggs.
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Zoospores - Reproductive Structure of the Phytophthora Buckeye rot of tomato is soil-borne and therefore affects fruit lying on, or close to, the soil. The fungi are spread by surface water, spattering rain, and furrow irrigation. While it can sexually reproduce through the production of oospores, its primary form of reproduction is by asexually producing sporangia. These sporangia are found at the tips of sporangiophores that emerge through the stomates.
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Close up of aecia of Puccinia sessilisAn aecium (plural aecia) is a specialised reproductive structure found in some plant pathogenic rust fungi that produce aeciospores. Aecia may also be referred to as "cluster cups". The term aecidium (plural aecidia) is used interchangeably but is not preferred. In some rust fungi such as Phragmidium, aecia lack an outer wall structure (a peridium) but instead produce a diffuse aecium called a caeoma.Fungi.
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Both can form abundant protoperithecia, the female reproductive structure (see Figure). Protoperithecia are formed most readily in the laboratory when growth occurs on solid (agar) synthetic medium with a relatively low source of nitrogen. Nitrogen starvation appears to be necessary for expression of genes involved in sexual development. The protoperithecium consists of an ascogonium, a coiled multicellular hypha that is enclosed in a knot-like aggregation of hyphae.
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The scrotum is an anatomical male reproductive structure located caudal to the penis that consists of a suspended dual-chambered sack of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum contains the external spermatic fascia, testes, epididymis, and ductus deferens. It is a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein, and pampiniform plexus.
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Angiosperm life cycle Double fertilization refers to a process in which two sperm cells fertilize cells in the ovule. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells.
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This young specimen shows the characteristic color, cap warts, and stem that are typical of this species. An immature fruit body can be seen to the right. Like all Amanita species, the bulk of the organism lies beneath the ground as a symbiotic partner to certain species of trees. The fruit body of the fungus is a reproductive structure that appears when appropriate environmental conditions of moisture, temperature, and nutrient availability are met.
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Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment of the parent plant or a specialized reproductive structure. Many plants naturally reproduce this way, but it can also be induced artificially. Horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. Success rates and difficulty of propagation vary greatly.
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The zombie-ant fungus is easily identifiable when its reproductive structure becomes apparent on its dead host, usually a carpenter ant. At the end of its life cycle, O. unilateralis typically generates a single, wiry yet pliant, darkly pigmented stroma which arises from the dorsal pronotum region of the ant once it is dead. Moreover, perithecia, the spore-bearing sexual structure, can be observed on the stalk, just below its tip. This complex forms the fungus’ fruiting body.
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After an infective female cyprid larva has settled on a suitable host, it pierces the cuticle with its antenule and injects some cells into the abdomen of the hermit crab. These develop internally, sending out root-like processes into the surrounding tissues. The parasite has no gut, but after about three months, the externa pushes through the crab's abdomen. This is essentially a reproductive structure on a stalk, with a large ovary and a brood chamber.
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Because the family is defined loosely on stem structure with nothing known about the foliage and reproductive structure, different genera have been added and removed from this family. The four genera, Bilignea, Eristophyton, Endoxylon, and Sphenoxylon, were added to the family in 1936. These genera were classified by their pycnoxylic secondary wood pattern, and in 1953, they were removed from the family with the intention of keeping the family composed of genera with monoxylic secondary wood.
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The parts of a flower Double fertilization Double fertilization in Arabidopsis Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through style.
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A stained preparation of the cell Bacillus subtilis showing endospores as green and the vegetative cell as red Phase-bright endospores of Paenibacillus alvei imaged with phase-contrast microscopy An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Firmicutes. The name "endospore" is suggestive of a spore or seed-like form (endo means within), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself.
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European honey bee carrying pollen in a pollen basket back to the hive Marmalade hoverfly, pollen on its face and legs, sitting on a rockrose. Diadasia bee straddles flower carpels while visiting yellow Opuntia engelmannii cactus The transfer of pollen grains to the female reproductive structure (pistil in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Anemophilous plants typically produce great quantities of very lightweight pollen grains, sometimes with air-sacs.
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Armillaria mellea Armillaria hinnulea The basidiocarp (reproductive structure) of the fungus is a mushroom that grows on wood, typically in small dense clumps or tufts. Their caps (mushroom tops) are typically yellow-brown, somewhat sticky to touch when moist, and, depending on age, may range in shape from conical to convex to depressed in the center. The stipe (stalk) may or may not have a ring. All Armillaria species have a white spore print and none have a volva (cup at base) (compare Amanita).
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They have a single, flat, rounded bilateral shell that is often thin and fragile; it ranges in size from 3 to 30 millimetres (in recent species). The apex of the shell is at the anterior end. The fossil shells exhibit a series of muscular attachment scars on the inner side, suggesting metamerism; indeed, with living Monoplacophora to study, it can be seen that their body segments exhibit a serial repetition of kidneys, gills and reproductive structure. This used to be interpreted as a true segmentation, which suggested a "missing link" between mollusks and annelids.
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The most striking characteristic of Dorstenia is their reproductive structure, called pseudanthium (Greek for "false flower") or in Moraceae hypanthium, which is composed of clusters of tiny unisexual flowers on a disc- or cup-shaped receptacle that are often adorned with bracts of various sizes and shapes. The pseudanthiums can be planar, convex, concave, round, oval, square, lobed, twig, star, boot, or tongue-shaped. Their color varies from green to yellowish and reddish to violet and brown. Beneath the pseudanthium, there are usually bracts, scattered or in rows, sometimes carrying appendages.
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An anatomically preserved cone of Williamsonia has been discovered in Campanian rocks of Vancouver Island. This was the first reproductive structure of Williamsoniaceae to be recovered from western North America. Bennettitalean cones ( in length and in diameter) from the Crato Formation of Brazil may belong to Williamsonia, as well as finds from the Gristhorpe Beds of Cayton, England (in this case the specific species W. leckenbyi). In addition, W. harrisiana has been described from the Rajmahal Hills of India, as well as W. nizhoniamcdouldsd from the Chinle Formation of New Mexico.
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On a female bryophyte shoot, the reproductive structure is called the archegonium (plural: archegonia). The structure of an archegonium consists of: a sterile jacket that encloses the egg, a neck, a neck canal that allows the sperm to enter the archegonium to fertilize the egg, a venter that protects the egg and later develops into the calyptra, and the egg itself. When an egg in the archegonium of a female Pogonatum urnigerum shoot is fertilized, it matures and develops the sporophyte structure of the plant which sexually reproduces by producing and dispersing spores. The perichaetium structure is composed by an archegonium, paraphyses and perichaetial leaves.
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The dioecious genus is noted for the large size of the reproductive structure, and this species is remarkable in several of those aspects. The female cone measures wide and long, and the weight has been recorded up to ; the eggs and spermatozoids are visible to the naked eye. The cones persist on the plant for many months, the smaller pollen-bearing cone remaining green and the larger female cone becoming prominently red. Spores are contained in small box-like structures on the underside of the leaf until ripe, a similar structure at the receptive cone is reduced to two seeds that remain attached to the leaf.
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This incompatibility system is a specific mechanism employed by heterostylous species, where incompatibility is based on the positioning of the reproductive structure of the flower. In tristylous species this is based on two loci, S and M with one allele dominant at each loci. For the short- styled morph the dominant allele is in the S locus (Ssmm or SsMm), whereas in the mid-styled morph the dominant allele is at the M locus (ssMm). The S locus is epistatic to the M locus such that the presence of the S allele produces a short-styled flower regardless of the genotype at the M locus.
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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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The one-sex and two-sex theories are two models of human anatomy or fetal development discussed in Thomas Laqueur's book Making Sex: Body and Gender from the Greeks to Freud. He theorizes that a fundamental change in attitudes toward human sexual anatomy occurred in Europe in the 18th and 19th centuries. Prior to the eighteenth century, it was a common belief that women and men represented two different forms of one essential sex: that is, women were seen to possess the same fundamental reproductive structure as men, the only difference being that female genitalia was inside the body, not outside of it. Anatomists saw the vagina as an interior penis, the labia as foreskin, the uterus as scrotum, and the ovaries as testicles.
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The gametophyte is the first and dominant phase of two alternating phases in a bryophyte's life cycle. This part of the life cycle consists of protonema (the preliminary stage where the propagule develops green thread-like filaments), the rhizoids (filaments growing beneath the bryophyte that help anchor the bryophyte to its substratum), the stem, the leaves, its reproductive structure (archegonium in female plants, antheridium in male plants), and the calyptra (a thin tissue that forms from the venter of an archegonium and protects the sporangium as it develops). Pogonatum urnigerum has a wine-red stem. A leaf of P. urnigerium measures 2.5-6mm in length and consists of a unistratose lamina with many lamellae on the upper surface (adaxial side) of the leaf (30-46 lamellae stacked with pillars of 4-7 cells each).
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In some species of Hemiptera the adults remain with their aggregated immature offspring, sometimes in protective roles. The range of functions is very wide in detail, but among the more important classes of function are security against predators, success in food location, wide range of mate choice, with concomitant increase of outbreeding opportunities, location with other members of the same species (sometimes adherence to separate communities can almost amount to parapatric residence when say, different communities of rats or chimpanzees have violent mutual antipathy). There also are various forms of educational function, such as in some species where the young must learn the correct mate recognition skills, and in highly intelligent species such as crows and elephants, must learn the necessary social skills and the necessary traditional foraging techniques in their region. Aggregation activities are not restricted to the animal kingdom; for one example, a fundamental class of aggregations occurs in the various groups of slime molds, in which separate cells actually aggregate in the process of constructing their reproductive structure.
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