Sporangium of Pogonatum urnigerum with its nematodontous teeth. The sporophyte is the second phase in a bryophyte's life cycle. This phase consists of the foot (structure that supplies nutrients from the gametophyte to the developing sporophyte), the seta (the structure that elevates the sporangium), the sporangium (the structure where spores mature), and the operculum (a flap that covers the end of the developing sporangium). In Pogonatum urnigerum, the sporophyte structure takes 6 months to mature during spring and summer.
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The life cycle of Pilobolus begins with a black sporangium that has been discharged onto a plant substrate such as grass. A herbivorous animal such as a horse then eats the substrate, unknowingly consuming the sporangium as well. The Pilobolus sporangium survives the passage through the gastrointestinal tract without germinating, and emerges with the excrement. Once outside its host, spores within the sporangium germinate and grow as a mycelium within the excrement, where it is a primary colonizer.
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In stage III, after the development of the sporangium, there is a temporary cessation of growth. In stage IV, a subsporangial vesicle expands beneath the sporangium. This is followed by stage V, where the spore matures, and the region of hypha directly below the subsporangial vesicle continues elongating. Finally, in stage VI, the subsporangial vesicle bursts and throws the sporangium into the air.
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It bears 12-100 long yellowish green leaves, each fine, soft, and 8 to 45 centimeters long. The unspotted tan colored sporangium are 12 millimeters long and 5 millimeters wide. The velum covers a sixth to a quarter of the sporangium.
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Sporangium of the moss Funaria hygrometrica with well-defined annulus. In mosses, an annulus is a complete ring of cells around the tip of the sporangium, which dissolve to allow the cap to fall off and the spores to be released.
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The sporangium fully matures in autumn. The seta measures 1–4 cm in height and is composed of hydroids (water conducting cells), leptoids (conducting cells of sugar and other nutrients), stereids (thick walled cells that provide structural support) and parenchyma cells. Once the seta has elongated, a sporangium develops at the end of the seta. The sporangium has an operculum, epiphragm, columella, sporangial jacket, a spore bearing layer, and nematodontous teeth.
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Sporangium of Polypodium vulgare with annulus on the right. In leptosporangiate ferns, the annulus located on the outer rim of the sporangium and serves in spore dispersal. It consists typically of a ring or belt of dead water-filled cells with differentially thickened cell walls that stretches about two-thirds around each sporangium in leptosporangiate ferns. The thinner walls on the outside allow water to evaporate quickly under dry conditions.
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The presence of simple, stiff hairs on the sporangium is shared with Oreogrammitis and Radiogrammitis.
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They are arranged spirally. The wall of the sporangium typically lacks any pigment, but sometimes it may be streaked with brown. The velum covers less than a quarter of the sporangium. The megaspores are white in colour and measure 400 to 560 μm in diameter.
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Nematodontous teeth are composed of whole, thickened dead cells. Although nematodontous teeth are not hygroscopic, they may aid in spore dispersal through small movements (they do not move much). Before the sporangium has fully matured, it is enclosed within a hairy calyptra (developed from the venter of the archegonium) that falls off after the sporangium has matured. At maturation, the sporangium measures approximately 2-3mm in length, is cylindrically shaped, and light brown to red-brown in colour.
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B - Renaultia. 1, Fertile pinnule, nat size. 2, Sporangium, enlarged. C - Dactylotheca, as in B. D - Sturiella.
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Later, the fungus fruits to produce more spores. Pilobolus sporangium The asexual fruiting structure (the sporangiophore) of Pilobolus species is unique. It consists of a transparent stalk which rises above the excrement to end in a balloon-like subsporangial vesicle. On top of this, a single, black sporangium develops.
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Through the process of meiosis, haploid spores are produced and released through the gaps of the dehisced sporangium.
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Hence it is unclear whether sporangia were borne terminally or laterally. The sporangia were kidney-shaped (reniform), 1.0 to 1.6 mm wide and 0.5 to 0.8 mm high. The stem or stalk widened somewhat where it joined the sporangium. The sporangium wall contained swollen cells and had a 'bumpy' appearance.
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The name Cryptosporangium derives from: Gr . adj . kruptos, hidden; New Latin noun sporangium [from Greek noun spora (σπορά), a seed (and in biology a spore), and Greek noun angeion (Latin transliteration angium), vessel], sporangium; New Latin neuter gender noun Cryptosporangium, an organism with sporangia (spore containing vessels) covered or hidden by mycelium.
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In Pilobolus, contact with the surface causes a rupture at the columella, which releases the sporangium, which adheres to the new surface. In Utharomyces, contact with the surface ruptures the subsporangial swelling. This releases cytoplasm, which is used to glue the upper portion of the swelling containing the sporangium to the substrate.
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As characterized by the Andreaeopsida, Andreaea rupestris have small sporophytes which lack both an operculum and a seta. Instead of a seta, they have a pseudopodium derived from gametophytic tissue attached to the sporangium, extending from the perichaetium attached by a structure called the foot. Once fully mature, the sporangium will open along 4 vertical lines of dehiscence to release the spores inside. The sporangium is hygroscopic as it will dehisce in dry conditions to release spores from the gaps, and will close back up in moist conditions.
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They can be found growing on trees close to the coast, though some species are also found on rocks. Their shoots form small tufts to large mats across habitats, often intertwined with other mosses, including Orthotrichum species. Ulota reproduce using sexual structures, sporangium (plural: sporangia), that are terminal on the shoot. The calyptra covering the developing sporangium can be hairy or not hairy depending on the species, but the hairs extend from the sporangium base to the apex as opposed to the calyptra hairs of Polytrichum mosses which extend from the apex to the base.
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The heads of the archegonia have a mucilage which attracts the sperm, and the degeneration of the neck canal allows for the passage of sperm to the egg, resulting in fertilization. The fertilized egg develops into a sporophyte, which is diploid, and protected by a remnant of the archegonium now known as the calyptra. Inside the developing sporangium, haploid spores are generated via meiosis. The seta raises the sporangium into the air, and once the sporangium is mature, the operculum falls off and the spores are released into the wind.
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The size of the mature sporangium seems to have a 1:1 ratio with the size of the host cell. Therefore, if a host cell is smaller the mature sporangium will also be smaller and vice versa if the host cell is larger the sporangium will be larger as well (Garcés et al. 2012). All of the Parvilucifera species have alveoli, flattened vesicles under the plasma membrane, that can be empty or filled with cellulosic material. The free- living zoospores are biflagellated, with a longer anterior flagellum and a short posterior flagellum.
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Although these fungi only grow to be tall, they can shoot their sporangium, containing their spores, up to away. Due to an increase of pressure in the vesicle, the sporangium can accelerate 0–45 mph in the first millimeter of its flight, which corresponds to an acceleration of an incredible 20000 g. Using a mucus-like substance found in the vesicle of the fungus, the sporangium can adhere itself onto whatever it lands, thus completing its life cycle. The basionym of this species is Hydrogera crystallina F.H. Wigg. 1780.
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The recurved margin is wide. Each sporangium contains 32 dark brown to black spores. The vast majority of M. aurea individuals thus far examined are apogamous triploids, with a chromosome number of 90 present in both sporophyte and gametophyte. A few populations forming 64 spores per sporangium have reportedly been found, and are presumed to be sexual diploids.
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Spores are of two kinds and sizes, both globose, trilete. Megagametophytes and microgametophytes protruding through sporangium wall; megagametophytes floating on water surface with archegonia directed downward; microgametophytes remaining fixed to sporangium wall. The small, hairlike growths, known as trichomes or microgametical follicles, are not known to have any productive function, and are currently a biological mystery.
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Fruit bodies (gasterocarps) are typically roughly spherical in shape, with a persisting single or branched rhizomorph. The columella (the central sterile portion of the sporangium) are variable in size and shape. The peridium (the wall of the sporangium) is thin and short-lasting. The gleba is initially white, but later becomes colored by the masses of spores.
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In angiosperms, if the female sporangium is fertilised, it becomes the fruit, a mechanism for dispersing the seeds produced from the embryo.
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Sporophytes of mosses usually consist of the foot, which penetrates the gametophore, the seta, with an internal conducting system, and a terminal sporangium.
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The close proximity of the antheridia and archegonia helps facilitate fertilization. The antheridia contain sperm that travel down the neck of an archegonium, which houses the egg, to fertilize it. When the egg is fertilized and becomes a diploid zygote, it then develops into the diploid sporangium. Note that the sporangium is attached to a haploid pseudopodium that was derived from gametophytic tissue.
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Specimens were first attributed to Cooksonia caledonica by Edwards in 1970. According to a review of the genus Cooksonia by Gonez and Gerrienne, the sporangium of the type species (C. pertoni) is formed by a widening of the end of a stem. At maturity the sporangium is topped by a flattish disk (an operculum) and releases its spores when this breaks up.
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Sporangiospores (4-11 µm diam) are produced in the sporangium and are unicellular, ovoid and brown. Sporangiospores serve as the primary inoculum and are passively released when the outer layer of the sporangium breaks down. Other R. stolonifer structures include stolons and rhizoids. Stolons arch over the surface and rhizoids grow into the substrate at each point of contact between stolon and substrate.
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The sporangium of mosses usually opens when its operculum or "lid" falls off, exposing a ring of teeth that control the release of spores.
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In some phyla of fungi, the sporangium plays a role in asexual reproduction, and may play an indirect role in sexual reproduction. The sporangium forms on the sporangiophore and contains haploid nuclei and cytoplasm . Spores are formed in the sporangiophore by encasing each haploid nucleus and cytoplasm in a tough outer membrane. During asexual reproduction, these spores are dispersed via wind and germinate into haploid hyphae.
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Although sexual reproduction in fungi varies between phyla, for some fungi the sporangium plays an indirect role in sexual reproduction. For Zygomycota, sexual reproduction occurs when the haploid hyphae from two individuals join to form a zygosporangium in response to unfavorable conditions. The haploid nuclei within the zygosporangium then fuse into diploid nuclei.When conditions improve the zygosporangium germinates, undergoes meiosis and produces a sporangium, which releases spores.
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These zoospores form in plurilocular sporangium, and can mature into the sporophyte phase immediately. In a representative species Laminaria, there is a conspicuous diploid generation and smaller haploid generations. Meiosis takes place within several unilocular sporangium along the algae's blade, each one forming either haploid male or female zoospores. The spores are then released from the sporangia and grow to form male and female gametophytes.
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Each unit was made up of one or two bracts and a spore-forming organ (sporangium) between a bract and the stem. It appears that the sporangium released its spores by splitting along top. The arrangement of the sporangia resembles that of some zosterophylls, but the plant's discoverers considered its relationships uncertain. In 2013, Hao (one of the discoverers) and Xue listed the genus as a barinophyte.
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Nematodes have been observed climbing the sporangiophore or swimming inside of it to catch a ride on the sporangium. While many species may do this, it seems only Dictyocaulus vivipores, cattle lungworm, are able to survive the trip. Mechanisms of dispersal are less known in these genera. In both genera, the sporangiophore, guided by light, elongates until the sporangium is brought into contact with a solid surface.
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No single morphological character divides Myriopteris, as presently circumscribed, from the other cheilanthoids. Convergent evolution in arid environments is thought to be responsible for widespread homoplasy in the morphological characters traditionally used to classify this group. While small, bead-like ultimate segments are associated with the genus, they only appear in about 40% of its species, and appear in some cheilanthoids outside the genus as well. Cheilanthes sensu stricto bears 32 spores per sporangium in sexual species and 16 in apogamous species; with the exception of a few species of Notholaena, Myriopteris and the other cheilanthoids bear 64 spores per sporangium when sexual and 32 per sporangium when apomictic.
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Asplenium resiliens is a triploid and reproduces apogamously, producing 32 spores per sporangium. Specimens with 64 well-formed spores per sporangium, believed to be sexually reproducing, were collected from Green Gulch in the Chisos Mountains in 1937, although other specimens since collected in the area have the typical 32 spores per sporangium. While globally secure, it is considered an endangered species in many of the states at the northern edge of its North American range. NatureServe considers it to be critically imperiled (S1) in Colorado, Illinois, Indiana, Maryland, Mississippi, Nevada, Pennsylvania, South Carolina, and Utah, imperiled (S2) in Kansas and North Carolina, and vulnerable (S3) in West Virginia.
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Resting spores are developed in the fall and winter. Upon germination, the resting spore acts as a sporangium. The type, Synchytrium taraxaci, is placed in this subgenus.
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The gametophyte is unisexual and will produce either sperm or egg and not both at the same time. Sperm is transported, often by water, to an archegonium located on the top of a female gametophyte shoot. Once an egg has been fertilized, it develops a diploid sporophyte structure which is composed of a foot, seta, sporangium, and operculum. The foot supplies the developing sporangium with nutrients from the gametophyte.
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The seta elevates the sporangium. The sporangium develops within a hairy calyptra and produces spores through meiosis. Mature spores are dispersed through the openings of the sporangium's nematodontous teeth either by limited teeth movement or by wind. The small openings between the nematodontous teeth prevent all the spores from being dispersed at once which gives the sporophyte the advantage of dispersing spores over a longer period of time.
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Cryptomitrium is a genus of complex thalloid liverworts in the family Aytoniaceae. The genus name means “hidden turban” in reference to the inconspicuous sheath around the immature sporangium.
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After the operculum falls off, the sporangium is ready to reproduce through spore dispersal. Spore dispersal usually occurs in late spring the following year after the sporophyte has fully matured.
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Scanning and transmission electron microscopy has shown that the surface of the sporangium is covered with crystals of two distinct sizes. The larger crystals enclose spines having a central pore.
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Phycomyces is a genus of fungus in the Zygomycota phylum. They are known for their strong phototropism response and helical growth of the sporangium. The best studied species is Phycomyces blakesleeanus.
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A. limitanea may have slightly zig-zag axes, but its subdivisions are not as strongly spreading. Furthermore, this species is apogamous and only contains 32, rather than 64, spores per sporangium.
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Side branches bearing sporangia ultimately divided to produce a group of four sporangia, each with an outer leaf-like bract which folded around the sporangium. Celatheca resembles the Australian fossil Yarravia.
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For a sporangiophore less than 1cm tall, this involves acceleration from 0 to 20 km/h in only 2 µs, subjecting it to over 20,000 G, equivalent to a human being launched at 100 times the speed of sound. The orientation of the stalk towards the early morning sun apparently guarantees that the sporangium is shot some distance from the excrement, enhancing the chances that it will attach to vegetation and be eaten by a new host. Another adaptation of Pilobolus is that the sporangium is covered in calcium oxalate crystals. Besides serving as a protective mechanism, their hydrophobic nature also leads the sporangium to flip over onto its sticky bottom after landing in a drop of dew, thus allowing it to cling to a plant substrate.
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Each sporangium in a sorus carries 32 spores. Most individual sporophytes are apogamous triploids, with a chromosome number of 3n = 87. Sexual diploids with 2n = 58 are known from Nuevo Leon, Mexico.
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Hyphae are coenocytic and produce sporangiophores covered in calcium oxalate. Sporangiophores give rise to pedicellate, unispored sporangia. In many cases, the wall of the sporangium and the spore have fused.Kendrick, Bryce. 2000.
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Each sporangium contains 32 spores. The spores are covered with a network of raised crests, more densely fused and with smaller apertures between them than other South American members of the genus.
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It usually has 32 spores per sporangium, but many with only 16 have been observed, produced from eight 2n mother cells. It is diploid and has 60 chromosomes in its root tip cells.
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Mature sporangium of an Absidia mold Moss sporangia Sporangia (clustered in sori) on a fern leaf Scanning electron micrograph of fern leptosporangia Equisetum arvense strobilus cut open to reveal sporangia A sporangium (pl., sporangia) (modern Latin, from Greek σπόρος (sporos) ‘spore’ + ἀγγεῖον (angeion) ‘vessel’) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle.
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An annulus in botany is an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores.
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The spores are brown, subglobose or ovoid, punctate (spotted), 5–7 µm in size and dispersed by wind and rain until only a few delicate threads of the sporangium remain, resembling soft foam padding.
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Unicellular spores are produced through meiosis by the sporophyte. In Splachnaceae, they are often small and sticky for easy insect dispersal. Spores are sometimes dispersed in clusters. Sporangium of Splachnum ampullaceum, showing the exaggerated hypophysis.
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This is done through a process in which the haploid nucleus – a nucleus with half the number of chromosomes for that species – is encased in an outer membrane with a cytoplasm. The haploid nucleus within the sporangiophore fuses with the cytoplasm to create diploid nuclei (spores) – a nucleus with the normal number of chromosomes for a specific species -. These spores then travel through the sporangiophore where they reach the sporangium. The sporangium is the structure within the fungi that is reliant on storing spores.
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Light microscopy of a leaf of U. bruchii showing the rectangular hyaline cells along the margin of the leaf. A mature sporangium of U. crispa showing the ribs along the sporangium wall. Ulota mosses tend to grow in a tuft on the substrate, with the shoots growing in an acrocarpous fashion with the shoots standing up. The tufts can vary in colour, ranging from a deep green at the top of the tuft to a darker brown/red at the base of the cushion.
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The immature sporophyte then grows out from the archegonial venter. A sporophyte contains a seta (that holds up the sporangium), a capsule with an operculum cap, and a coat enclosing the capsule called the calyptra that grew from the venter of archegonia and is the only haploid structure in sporophyte. When the sporophyte is fully mature the calyptra falls off and reveals the peristome teeth within. Meiosis occurs in the sporangium and haploid spores are produced and released through the control of peristome teeth.
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They are persistent after the spores mature, but may be hidden by the full sporangia. A. resiliens has a chromosome number of n = 2n = 108 and produces 32 unreduced, round or egg-shaped spores per sporangium.
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Pine pollen under the microscope A late Silurian sporangium bearing trilete spores. Such spores provide the earliest evidence of life on land. Green: A spore tetrad. Blue: A spore bearing a trilete mark – the Y-shaped scar.
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The plants are dioicous, with separate plants producing the male and female organs. Male plants develop only one microscopic leaf around each antheridium, and female plants produce just three or four tiny colorless leaves around each archegonium. Because of its small size, the gametophyte stage is not generally noticed until the stalked sporangium develops, and is locatable principally because the sporangium grows upon and above the tiny gametophyte. The extremely reduced state of Buxbaumia plants raises the question of how it makes or obtains sufficient nutrition for survival.
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No sexual reproduction cells or structures have been identified yet, but the asexual reproduction cycle is well understood. Aplanochytrium multiply through spores produced by binary fission and held within the parent wall to form a spherical colorless sporangium. These daughter cells are called aplanospores and are not flagellated. Ten to fifty of these spores are released either due to the complete disintegration of the cell wall or through the production of tears at one or two points in the cell wall, through which the spores can leave the sporangium.
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Through experimental studies, for the species P.sinerae salinity may also play a significant role in terms of germabilit, as it was found that lower salinity levels would promote higher infection rates (Figueroa et al. 2008). P. infectans and P.sinerae have been able to survive extreme conditions due to the resilience of sporangium in the host cells which can protect the zoospores, alongside the protection of the host cyst. The Parvilucifera sporangium has been found to be able to survive cold temperatures for many months (Lepelletier et al. 2013).
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Asexual reproduction occurs by the formation of uninucleate, haploid sporangiospores in the sporangia, on the terminal ends of the aerial sporangiophores. In the sporangia, there is an accumulation of nutrients, cytoplasm, and nuclei. An extension of the sporangiophore called the columella protrudes into the sporangium, and upon the maturation of the sporangiospores, burst of the sporangium allows for the dispersion of the spores, where wind is the primary dissemination method. Asexual reproduction may be favoured in unfavourable environmental conditions, as this inhibits the conjugation between the two sexual strains.
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The pathogen Aphanomycete cochlioides, like most oomycete fungi, survives and overwinter as oospores in plant debris or soil. When the soil warms in the spring the oospores receive signals to germinate. The oospores have the ability to directly infect the root in the soil but it is more common for the oospore to play a smaller role in the life cycle producing a specialized hyphae called sporangium. The sporangium has the ability to produce zoospores- which have two different types of flagella, tinsel and whiplash, that allow them to be motile in soil water.
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The adjacent vegetative cells (any of the cells of a plant or animal except the reproductive cells) are smaller in size and are filled almost completely with densely packed physodes (any of various vesicular intracellular inclusions of brown algae that are of uncertain constitution and function). As the sporangium develops and enlarges further the nucleus and chloroplasts divide a number of times. The sporangium is egg- shaped and lies within the cortical (cells in the cortex) and medullary (or pith) cells. It is slightly narrower where it touches the surface.
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Newburyport, MA. In Pilobolus, the subsporangial swelling acts as a lens to focus light on light-sensitive pigments at the base of the swelling. Turgor pressure builds inside of the swelling until it ruptures, and the sporangium is hurled for 2 meters. The calcium oxalate crystals helps it adhere to the surface it lands on, and if the surface is wet, the crystals allow the sporangium to rotate. This rotation allows the mucus surrounding the spores (under the crystals) to glue it to surface where it will await ingestion by an herbivore.
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Fluxes are in T mol Si y−1 (28 million metric tons of silicon per year) Pennate diatom from an Arctic meltpond, infected with two chytrid-like [zoo-]sporangium fungal pathogens (in false-colour red). Scale bar = 10 µm.
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Like some other Chytridiales, Synchytrium endobioticum develops no mycelium. The fungus produces a thick walled structure known as a winter sporangium. It is 25-75 µm in diameter and contains 200-300 spores. Sporangia are clustered into thin- walled soruses.
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Some authors have interpreted what appear to be petals as petaloid staminodes. The stamens are 10 to 15 in number. The anthers are basifixed, as in all of Hamamelidaceae. Each theca has one sporangium, whereas for most angiosperms, there are two.
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The sori lie along the veins, in the portions closest to the edge of the leaf. The leaf edges are not modified into false indusia. Each sporangium bears 64 spores. The plants are diploid, with a chromosome number of 2n = 54.
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The sporangium (spore-forming organ) is unique among both living and fossil plants, consisting as it does of branched lobes at the apex of some of the branches of the stem. Each lobe contains a central collumella, analogous to the sporangia of hornworts; however, the sporangia of hornworts are not branched. The number of lobes possessed by a sporangium varied; at least three orders of dichotomous branching have been found, resulting in more than four lobes. The sporangia were much less regular than shown in most reconstructions (including that opposite), and they had 'bumps' or emergences on them.
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Recorded on 26 Aug 2015. It bears 10–30 green to yellow leaves and a two-lobed corm. The velum covers one to three quarters of the sporangium, which are long. Round white megaspores are about in diameter and are covered with spines.
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This class is also well known for a hairy calyptra that is present in many Polytrichopsida mosses which functions to protect the developing sporangium. Some species of Polytrichum also have biseriate paraphyses in its perigonium (composed of an antheridium, paraphyses and perigonial leaves) structure.
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The spines are tapered and pointed lower on the plant but form loose spikes at end of the plant. The sporangium split along convex margins into equal valves in a trilete fashion.The xylem are just one solid strand. The epidermal cells have cuticular papillae.
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It is two millimeters in diameter, and inside are numerous male sporangia. Male spores (microspores) are extremely small and are produced inside each microsporangium. Curiously, microspores tend to adhere in clumps called massulae. Female sporocarps are much smaller, containing one sporangium and one functional spore.
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Genera are distinguished by their peristome teeth. Voitioideae (Voitia) is characterized by the absence of a differentiated line of dehiscence on the sporangium (cleistocarpy). Spore dispersal is only achieved following the decay of the sporangial wall. Species in this subfamily are coprophilous but not entomophilous.
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The algae has a latent period of roughly a year following the initial infection of damaged tissue. After this time, it will begin fruiting during rainy periods. It disperses as both motile zoospores, and also through wind-borne sporangium. Wind and rain are mechanisms of this dispersal.
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There is one sporophyte produced per perichaetium. The seta, which is a stalk that supports capsule, is relatively short and is 25 mm in length. It is red-brown in colour and inserted laterally. The operculum (lid) is about the same length as the rest of the sporangium.
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Cells of the genus Aplanochytrium multiply by forming aplanospores in a spherical sporangium. The spores are then released and they move away by crawling along their own ectoplasmic thread. The aplanospores are non-flagellated asexual spores. Aplanochytrium is found exclusively in marine environments and lives on diverse host organisms.
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Symptoms of this pathogen include stunting and chlorosis. Identifying Pythium ultimum has traditionally been done by examining oogonia, antheridia, and sporangium structure. Now, PCR (polymerase chain reaction) technology can identify the pathogen using DNA fragments. Phytophthora cactorum is a pathogen that causes root rot on many plant species.
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Their thalli (=bodies) consist of two parts: an absorptive branching rhizoidal system that contains no nuclei and a multinucleate sporangium that ranges in shape from spherical, to oval, to pear-shaped, and to multi-lobed. The rhizoids attach the thallus to a substrate (food source) and absorbs nutrients. When the thallus is fully grown, the sporangium releases numerous, unwalled, uninucleate-zoospores, each bearing a single posteriorly directed flagellum. The zoospore has to use its own stored food reserves (lipids and glycogen) as it swims until it attaches to a suitable host or substrate, absorbs its flagellum, produces a wall around itself, grows a germ tube that penetrates the substrate, and develops into a new thallus.
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The sporangiophore has the remarkable ability of orienting itself to point directly towards a light source. The shape and transparency of the subsporangial vesicle allow it to act as a lens, focusing light into carotenoid pigments deposited near the base of the vesicle, which absorb the photons and allow cells to detect the light level in the direction of the lens. The developing sporangiophore grows such that the maturing sporangium is aimed directly at the light. When turgor pressure within the subsporangial vesicle builds to a sufficient level (often 7 ATM or greater), the sporangium is launched, and can travel anywhere from a couple of centimeters to a distance of 2 meters (6 ft).
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While the three clades of Schizaeales are all well-distinguished from one another by numerous morphological characters, members of the order all have dimorphic fertile and sterile fronds and lack well-defined sori. Their sporangia have a horizontal annulus that lies below and completely encircles the top of the sporangium.
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Morphological adaptations of the family Splachnaceae include the enlarged, often inflated hypophysis, the coloured sporangium/upper region of the seta, and hygroscopic movements of the peristome which help spores to leave. As well, the small spore size and stickiness helps spores to be dispersed in clumps on the hairs of insects.
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Pennate diatom from an Arctic meltpond, infected with two chytrid-like [zoo-]sporangium fungal pathogens (in false-colour red). Scale bar = 10 µm. 50px Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Marine fungi have been observed as far north as the Arctic Ocean.
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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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The velum covers one fourth to one third of the orbicular sporangium, which is 5 to 6 millimeters in diameter. The ligule is shaped like a shortened triangle. The white megaspores are 500 to 700 micrometers in diameter and bear sharp ridges and crests. The microspores are 36 to 43 micrometers long.
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The leaf edges are not modified into false indusia, and may be flat or curled under to cover the sori. Each sporangium bears 64 spores. The plants are diploid, with a chromosome number of 2n = 54. The zig-zag rachis and axes generally serve to distinguish it from other members of the genus.
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These L1 larvae are shed in the feces or manure. In the feces, larvae mature through two stages and become infective as L3 stage larvae. Cattle feces supports the growth of Pilobolus sp. fungi. The L3 larvae of D. viviparus invade the inside of these fungi, and wait in the fungal sporangium.
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Rhytidiadelpus loreus is a dieocious plant that has both male and female reproduction capabilities in independent individuals. The sporophytes have an irregular formation and growth pattern. The species reproduces occasionally and seemingly sporadically. The sporophytpes protrude out of the stem, 2 to 6 centimeters long, into a long stalk forming a sub-spherical sporangium.
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These plants are described by Hueber as having monopodially branched stems, that are unridged, spinous and circinately tipped. The sporangia are described as round in abaxial view, and oval in lateral view. These sporangia are formed laterally and singular on short stalks. The sporangium split along convex margins into equal valves in a trilete fashion.
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The rupturing of the sporangium releases a large mass of spores into the environment, this enable the fungi to reproduce rapidly. Fungal species are also able to reproduce asexually via budding. Budding refers to the process in which an offspring is formed from a parent cell. This occurs for Entomophthora cells already within a host.
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Species of Dipteris grow from creeping rhizomes,F. O. Bower and have large stalks to the sporangium and annulus. The rhizomes have bristles (or hairs) and the fronds have uniseriate hairs (having one line or series). All species of Dipteris have spore-capsules that are carried on the lower surface of the broad lobed frond.
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The Aphelidium plasmodium then proceeds to divide into uninucleate cells which develop into zoospores, using the cell wall of the host alga as a sporangium. Finally, the uniflagellate zoospores erupt the husk of the host cell via the same puncture made by the infection tube of the parent Aphelidium to seek new green alga hosts.
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Phytophthora cactorum P. cactorum requires free water to reproduce. Zoospores are released from sporangium and blown via wind or rain splash and use free water on the leaf to germinate. An appressorium is formed and a penetration peg penetrates the leaf surface. From there, hyphae grow throughout the leaf and infects all plant tissues.
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Fertile fronds bear a large number of sori underneath, long, which are not arranged in any particular order. The sori are often fused where veins join, and may curve to follow the vein to which they are attached. The sori are covered by inconspicuous thin, white indusia with untoothed edges. Each sporangium in a sorus carries 64 spores.
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Isoetes caroliniana, common name Carolina quillwort, is a wetlands plant native to the mountains of Tennessee, North Carolina, Virginia and West Virginia. It is an emergent plant found in lakes and bogs. It is closely related to I. georgiana (the Georgia quillwort) but can be distinguished by its unpigmented sporangium wall.Flora of North America vol 2.
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Life cycle of moss. Through its life cycle, Pogonatum urnigerum alternates between a haploid and diploid life cycle. The haploid structures include: the spores, the protonema, the rhizoids, the leaves, the reproductive structures, the calyptra (developed from an archegonium) and the stem of the gametophyte. Diploid structures include: the foot, the seta, the sporangium, and the operculum.
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Trichia varia is a type of slime mold in the order Trichiida. Its sporangium measures 0.6 to 0.9 millimeters, and its stalk 0.1 to 0.5 millimeters. It is a pale orange color, distinguished by other members of its genus by having two spiral bands on its elaters. It is distributed throughout various parts of the world.
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All three species share cellular dimensions and morphology. All form oval spores located centrally in an unswollen sporangium. B. anthracis endospores, in particular, are highly resilient, surviving extremes of temperature, low-nutrient environments, and harsh chemical treatment over decades or centuries. The endospore is a dehydrated cell with thick walls and additional layers that form inside the cell membrane.
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Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins. A basidium (pl., basidia) is a microscopic sporangium (or spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly coiled secondary mycelium, a dikaryon.
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Sporangia may have formed a two-rowed spike or strobilus. Spores were shed via a slit at the top of the sporangium between thickened valve borders. Spores were of one kind, about 67 µm in diameter, without trilete marks. What are thought to be the underground stems of Ventarura had single-celled hairs, presumably rhizoids, on all sides.
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The leaves are usually dark green, though can occasionally be tinged with red. The sporangium can be up to five millimeters long and 3 millimeters in length, covered one sixth to one third by the velum. The spherical megaspores are 400-570 micrometers in diameter, and bear smooth ridges. The kidney shaped microspores are 25 to 30 micrometers long.
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When liberated, the sporangia inside the pustules are spread by wind, rain, and insects. After landing on a susceptible plant, each sporangium gives rise to about six zoospores which, under suitable conditions of moisture and light, form germ tubes which invade the plant's tissues. Zoospores are naked (wall-less), kidney-shaped and bi-flagellate. Both flagella are inserted laterally.
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They can be distinguishable from Rhizopus stolonifer as they have smaller sporangia and spores. The optimal conditions for sporangium production are temperatures between 30 °C to 35 °C and low water levels. Sporulation is stimulated by amino acids (except L-valine) when grown in light, while in darkness only L-tryptophan and L-methionine effect stimulation of growth.
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Megaspores number up to 36 per sporangium, gray-green, drying olive green, each up to 320 μm in diameter, covered with tubercules (bumps) over most of the surface. Microspores are brown, up to 25 μm in diameter.Musselman, Lytton J. & Roux, Jacobus Petrus. 2002. Isoetes toximontana (Isoetaceae), a new quillwort with green megaspores from the Northern Cape of South Africa.
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The production of aplanospores (autospores) in the second way leads to the development of 16-32 spores in the sporangium. For many years, no sexual structures or observation of sexual reproduction in Trebouxia were observed.Friedl, T., & Rokitta, C. (1997). Species relationships in the lichen alga Trebouxia (Chlorophyta, Trebouxiophyceae): molecular phylogenetic analyses of nuclear-encoded large subunit rRNA gene sequences.
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Sexual recombination is rare and occurs when mycelium of two compatible strains come in contact. Progametangia from each strain grow towards each other and fuse into gametangia, forming a thick-walled zygospore. Zygospores germinate to form sporangiophores bearing a single sporangium. R. stolonifer is incapable of breaching the intact root periderm and requires a wound to initiate infection.
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Spores appear to have been released through the appearance of an opening in a depression around the top of the sporangium, not sufficiently wide to result in its disintegration into two valves. Rogerson et al. say that this is the earliest evidence for "predetermined" dehiscence (opening to release spores). Triradiate spores with fine surface markings were found.
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14 January 2014. Spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new sporophyte.
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Cavitation plays a role in the spore dispersal mechanisms of certain plants. In ferns, for example, the fern sporangium acts as a catapult that launches spores into the air. The charging phase of the catapult is driven by water evaporation from the annulus cells, which triggers a pressure decrease. When the negative pressure reaches approximately 9MPa, cavitation occurs.
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The false indusia are somewhat different in appearance and texture of the leaf tissue, and are 0.05 to 0.25 mm wide. Beneath them, the sori are more or less continuous around the margin of the bead-like leaf segments. Each sporangium in a sorus carries 32 brown spores. The triploid sporophyte has a chromosome number of 90.
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Scanning electron micrograph of a frozen intact zoospore and sporangia of the chytrid fungus (Batrachochytrium dendrobatidis), CSIRO B. dendrobatidis infects the keratinized skin of amphibians. The fungus in the epidermis has a thallus bearing a network of rhizoids and smooth-walled, roughly spherical, inoperculate (without an operculum) sporangia. Each sporangium produces a single tube to discharge spores.
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The sporangiospores are asexual mitospores (formed via mitosis), produced inside sporangia (thousands of spores) or sporangioles (single or few spores). They are released when mature by the disintegration of the sporangium wall, or as a whole sporangiole that separates from the sporangiophore. The sporangiospores germinate to form the haploid hyphae of a new mycelium. Asexual reproduction often occurs continuously.
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Also, the peridium (the outer layer of the spore-bearing organ) is sometimes short-lasting (evanescent). Columella (the central, sterile part of the sporangium) may be absent or present, the hymenia are not gelatinized, and are formed in locules. Basidia are club-shaped (clavate), with two or four sterigmata, sometimes with accompanying cheilocystidia (cystidia on the edges of gills).
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The sori lie along the veins, in the one-third to one-fourth of the vein closest to the leaf edge. The leaf edges are curved under, but not otherwise modified into false indusia. Each sporangium contains 64 spores. The spores are covered with a network of raised crests, although portions of the surface lack elevated crests.
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Each sporangium holds 64 spores. The species has a chromosome number of 144 in the sporophyte, indicating an allotetraploid origin. A. pinnatifidum is somewhat similar to its parent species A. rhizophyllum. In comparison, however, A. pinnatifidum is distinctly lobed when mature, tends to have longer stipes in proportion to its leaf size, and has a more upright habit.
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The top of the cone carries microsporophylls, the lower part megasporophylls, and both types may intercallated midlength. Sporophylls are disposed from the bottom up. Both types are obovate, with a round to ovoid sporangium and a tongue-like extension nearer to the tip on the upper/inner side. The trilete microspores are hollow, round and 30–40 μm in diameter.
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The edges of the indusia are not toothed or lobed. Beneath them, the sori are usually not continuous around the edge of the leaf, and are often concentrated on lateral lobes of the fertile pinnulets, particularly at the ends of veins. Each sporangium in a sorus carries 64 tan spores. Individual sporophytes are sexual diploids, with a diploid chromosome number of 2n = 58.
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They are easily washed off and each detached sporangium contains a short pedicel. The average size of the sporangia is 50×33 µm with a length of about 1.6 times longer than it is wide. Sporangia germinate directly in a nutrient medium by producing germ tubes that develop into mycelial masses. In water, however, zoospores are released from germinating sporangia.
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They were all of one size, up to 30 µm in diameter. In one specimen, two stomata were found immediately below the attachment of a sporangium to the stem. The best preserved is circular, around 35 µm in diameter, with two guard cells. Hollandophyton was (at least in 2002) the oldest fossil on which both stomata and sporangia have been found.
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This fungus normally grows beneath the surface – a sensitivity to oxygen inhibits radial growth at the hyphae. According to McVickar (1942), and later amended by Ootaki et al. (1993), the development of P. crystallinus may be divided into six stages: In stage I, the sporangiophore initially elongates at the apex, but does not rotate. In stage II, the sporangiophore develops a sporangium.
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The other kind is the sporangium, which is a round case that holds a mass of spores. An example of this is Hemitrichia clavata, which forms small sporangia held on a stalk that open to reveal brightly red to yellow coloured mature spores. These spores will then disperse and change into the haploid ameoboflagellate stage, starting the process over again.
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Despite the significant differences of morphological characteristics of sporangia and the manner of sporangium formation, these two species are associated, usually in medical literature, due to similar disease manifestation in human: cutaneous or subcutaneous infections. Infections involving these two species (S. vasiformis and A. elegans) cause rapid necrotizing vasculitis that leads to thrombosis and tissue necrosis in organisms’ vascular lumen.
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Many species in this family have very exaggerated sporophytes that are highly adapted for their specific ecological relationships. The seta of Splachnaceae is usually elongate and erect, with a defined central strand. The sporangium is highly variable in shape. In many species, the middle of the sporophyte (hypophysis/apophysis) may be highly inflated or flared in order to attract insects.
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Upon germination, a new haploid mycelium or sporangium is formed. Some species are homothallic. The original report of sex in fungi, occurred two centuries ago, based on observations of the fungus Syzygites megalocarpus (Mucoromycotina) (reviewed by Idnurm). This species, was subsequently used in 1904, to represent self-fertile species when the concept of two major mating strategies were developed for the fungi.
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The erect, stalked cylindrical sporangia are arranged into bundles or clusters that are tall. Each sporangium is supported by a thin, shining, black stalk that is long. The bright rusty brown color of mature sporangia lightens to a pale brown after the spores have been dispersed. Spores measure 5 by 7 μm and have a smooth to minutely punctate surface texture.
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Species in this subgenus are long cycled and begin as a uninucleate thallus that functions as a prosorus. Basically, the primary nucleus of the parasite grows within the host cyctoplasm. At a point, it will produce a new germ tube and exits out of the envelope. It then divides numerous times with each daughter nucleus partitioned into a developing sporangium.
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Alicyclobacillus macrosporangiidus is a species of Gram positive, strictly aerobic, bacterium. The bacteria are acidophilic and produce endospores. It was first isolated from soil in a crop field in Fujieda, Japan. The species was first described in 2007, and the name is derived from the Latin macros (big) and sporangium (sporangia), referring to the large spores produced by the organism.
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The overall life cycle of most Parvilucifera consists of an infective stage of free-living zoospores, the intracellular stage: trophont (feeding stage), and a resting sporangium that forms inside the host cell (Alacid et al. 2015). The endoparasites once having infected the cell will degrade the cytoplasmic contents of the host cell, describing the trophont stage. As this the process of feeding continues the contents of the host cell will become entirely degraded or pushed to the outer edges of the cell. As the trophont stage comes to an end, the sporangium should be developing, which will further give rise to numerous zoospores which will eventually be released out of the cell through the operculum of the apertures, unless it is P.prorocentri in which case the zoospores would be released through the germ tube (Reñé et al. 2017).
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Phomalactone (5,6-dihydro-5-hydroxy-6-prop-2-enyl-2H-pyran-2-one) is found to be produced by N. sphaerica. It inhibits mycelial growth of plant pathogenic fungi, Phytophthora infestans. The metabolite also inhibits sporangium and zoospore germination of both P. infestans and Phytophthora capsici. The study also shows that the metabolite reduces progression of late blight disease in tomatoes caused by P. infestans.
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The precise arrangement of the sporangia on the stems cannot be determined; there may have been zones of sporangia. Spores were released through a slit opening along the margins of the two valves of a sporangium. The trilete spores were about 55 µm in diameter. Hairless stems bearing rhizoids but with a similar anatomy to the aerial stems are possibly the rhizomes of Trichopherophyton.
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A presporangium is delimited by an envelope of scales, which build a rather thick membrane. The presporangium is further divided into sporangia, and in some species into a sori, until each of them contain eight zoospores. The zoospores are released directly into the ectoplasmic net, where they swim away from the sporangium. The morphology of the zoospore is similar to a "standard" stramenopile cell.
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The sporangium can be 5 millimeters long and 4 millimeters wide, covered from one sixth to one quarter by the velum. The triangular ligule can grow up to 2 millimeters long. The spherical, white megaspores are 400 to 800 micrometers in diameter, and bear ridges that form honeycomb-like areas. The kidney-shaped microspores are 32 to 50 micrometers long, each with evenly spaced smooth papillae.
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The leaf edges are not modified into false indusia; they are sometimes, thought not always, slightly curved under. Each sporangium bears 64 spores, indicating that it is a sexual diploid species. It is most similar to Argyrochosma jonesii, but can be distinguished from it by its black (rather than brownish) leaf axes, and the bipinnate (rather than bi- to tripinnate) division of the leaf.
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Sporangia were flattened, more-or-less circular to kidney- shaped (reniform) in face view, and upright on stalks about 2.5 mm long. They were relatively large, typically up to about 4 mm high and 4 mm wide, although a few were significantly larger. To release its spores, a sporangium split into two 'valves' along a thickened margin at the top. Spores have not been observed.
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In water, chlamydospores germinate by producing short germ tubes, each with a sporangium at the tip. Sexual reproduction in Phytophthora palmivora requires the presence of opposite mating types known as A1 and A2. Both A1 and A2 isolates can produce zoospores by selfing when stimulated by sex hormones produced by A2 and A1, respectively. Light is inhibitory to zoospore formation but stimulatory to zoospore germination.
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Each sorus includes a mix of two types of sporangium, each type producing only one of two kinds of spores. Toward the center of each sorus and developing first are the megasporangia, each of which will produce a single large female megaspore. Surrounding them at the edge of the sorus and developing later are the microsporangia, each of which will produce many small male microspores.
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Myriopteris newberryi has leaves up to about 30 centimeters long which are coated in matted white, gray, or brownish hairs. Each leaf is made up of subdivided segments where the ultimate segment is oval in shape, mostly flat, and hard to visualize due to its thick coat of hairs. On the underside are scattered sori containing sporangia. Each sporangium may have either 64 or 32 spores.
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Mature sporangia appear as dark-brown spots on the thallus. The entire contents of a sporangium are discharged together with a mass of sticky material. As it slowly disperses the meiospores swim free. The side biflagellate (has two flagellate) meiospores contain one chloroplast with an eyespot (eyespot apparatus) and are capable of motion for a relatively short period of no more than 15 min.
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Junggaria has some affinities with the rhyniophytes in that it has leafless dichotomizing stems with terminal sporangia and appears to have xylem. Rhyniophytes or paratracheophytes are part of the group from which the true vascular plants or tracheophytes are believed to have evolved. However, features of the sporangium led Cai et al. to make comparisons with genera such as Renalia, Sartilmania and some species of Cooksonia.
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The edges of the leaf segments do not curl or fold to protect them. Each sporangium contains 64 spores. The spores are nearly smooth, unlike many members of the genus. The lack of joints at the leaf segment bases, very dark leaf and segment axes, and the presence of scales and farina on the rachis help distinguish it from other species in the genus, particularly A. incana.
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In the liverworts, elaters are cells that develop in the sporophyte alongside the spores. They are complete cells, usually with helical thickenings at maturity that respond to moisture content. In most liverworts, the elaters are unattached, but in some leafy species (such as Frullania) a few elaters will remain attached to the inside of the sporangium (spore capsule). Spores and two elaters of the liverwort Ptilidium.
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Within the sori, 64 spores are borne in each sporangium. The species is tetraploid, with a sporophyte chromosome number of 2n = 144. The smaller, ground-hugging fronds are lance-shaped, ranging from long and across. The basal half to two-thirds of the blade is cut into lobes; they are occasionally cut all the way to the rachis to form pinnae at the very base.
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Asterella californica is a complex thallic liverwort in the phylum Marchantiophyta. A. californica often grows as colonies of flat rosettes of light green, rigid thalli, with undersides dark wine-red to nearly black. The receptacles are rounded, with four lobes each bearing a single sporangium sheathed by a white tattered skirt. A. californica is dioecious with separate male plants often intermingled with female plants.
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Species in this subgenus develop in a similar fashion as those in subgenus Microsynchytrium, except that the resting spore functions as a sporangium during germination. In these species, the zoospores can develop into either a prosori, as in Microsynchytrium, or they can fuse to form a flagellated zygote. The zygote infects a host cell and becomes a resting spore. Synchytrium endobioticum is included in this subgenus.
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Part of the sporophyll typically extends downward to create a heel or other distal extension. A ligule can be found in a small pit distal to the sporangium. Though Lepidostrubus is the most common name for Lepidodendrales cones, the name has been used for specimens of any form of preservation and for both monosporangiate and bisporangiate forms, so taxonomic problems often ensue. Attempts to dissuade these taxonomic confusions have been made.
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The dictyostelids are another group formerly classified among the fungi. They are slime molds that feed as unicellular amoebae, but aggregate into a reproductive stalk and sporangium under certain conditions. Cells of the reproductive stalk, as well as the spores formed at the apex, possess a cellulose wall. The spore wall has three layers, the middle one composed primarily of cellulose, while the innermost is sensitive to cellulase and pronase.
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This is because the impressions are formed by aerenchyma tissue that developed in closely with the parichnos. Above the leaf scar was a deep triangular impression known as the "ligular pit" for its similarities to the ligule of Isoetes. In some leaf-cushions a second depression was present above the ligular pit. Though its purpose is unclear, it has been suggested that the depression may mark the position of a sporangium.
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Pinnae of the fertile fronds carry from one to twelve pairs of sori on their underside, each long. Each pair of sori forms a chevron, pointing towards the base of the pinna along its central axis. An indusium covers each sorus; these are whitish and translucent or silvery with a slightly toothed or erose (irregularly jagged) edge, soon withering to reveal the sori. Each sporangium in a sorus carries 64 spores.
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Plants consisted of bare stems (axes) ending in blunt tips. Lower down they repeatedly branched dichotomously; higher up they bore sporangium-bearing 'units' in two rows on opposite sides of the stems. These units branched, also dichotomously, before terminating in sporangia, so that there were clusters of up to 128 paired, downward curved sporangia, oval in shape and about 5 mm long. Spores were released through a longitudinal slit.
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They lack the columella and apophysis present in sporangiophores of many other species of the Mucorales. Due to the appearance of molds in this taxonomic order (a long stalk with a round, upward-pointing tip), members are often called "pin molds". Unlike other members of the Mucorales, Cunninghamella species produce only one spore in each sporangium. Sporangia form a halo around a central, round vesicle at the apex of a sporangiophore.
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A zygospore remains dormant while it waits for environmental cues, such as light, moisture, heat, or chemicals secreted by plants. When the environment is favorable, the zygospore germinates, meiosis occurs, and haploid vegetative cells are released. In fungi, a sporangium is produced at the end of a sporangiophore that sheds spores. A fungus that forms zygospores is called a zygomycete, indicating that the class is characterized by this evolutionary development.
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293x293pxThe asexual life cycle of Phytophthora infestans is characterized by alternating phases of hyphal growth, sporulation, sporangia germination (either through zoospore release or direct germination, i.e. germ tube emergence from the sporangium), and the re-establishment of hyphal growth. There is also a sexual cycle, which occurs when isolates of opposite mating type (A1 and A2) meet. Hormonal communication triggers the formation of the sexual spores, called oospores.
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As well as, the zoospores of P.prorocentri which are reniform and similar in size to P.rostrata (Reñé et al. 2016). The mature sporangium of all of the species of Parvilucifera, aside from P.prorocentri, are described as blackish. A characterizing difference of the P.sinerae species is the process of infection can follow two pathways depending on the host. The pathways can be identified as either cytoplasmic infection or nuclear infection.
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Under certain stress conditions some zoospore pairs fuse, resulting in a zygote. The zygote bearing host cells divide, forming eventually the walls of a new winter sporangium. In autumn, the warts rot and disintegrate, releasing new thick-walled resting spores of the fungus into the soil. The diploid resting spores (pro-soruses) undergo a dormancy period and before germination (probably) a meiotic division and several mitotic divisions, becoming a sorus.
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Then each of the four resulting branches was three times pinnate. Each ultimate unit had an elongated sporangium at its end which split longitudinally to release the spores which were trilete, ranging from around 70 to 170 µm in diameter. The complex three-dimensional branching pattern imples that both species would have been open bushy plants. The exact height cannot be determined from the fossils, which consist of broken-off portions.
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In mosses, liverworts and hornworts, an unbranched sporophyte produces a single sporangium, which may be quite complex morphologically. Most non-vascular plants, as well as many lycophytes and most ferns, are homosporous (only one kind of spore is produced). Some bryophytes, most lycophytes, and some ferns are heterosporous (two kinds of spores are produced). These plants produce microspores and megaspores, which give rise to gametophytes that are functionally male or female, respectively.
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Rozella polyphagi was first described in 1938 by F. K. Sparrow as a parasite of Polyphagus laevis, though it also parasitizes Polyphagus euglenae. Rozella polyphagi infects both the prosporangium and the sporangium of the host and exists as an unwalled protoplast within the host. Host mitochondria could be observed within R. polyphagi protoplast vacuoles; cytoplasmic extensions of R. polyphagi around host cytoplasm also occur. This suggests that Rozella polyphagi phagocytizes host cytoplasm.
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The midvein is often limited to the lower half of the leaf blade, or has completely disappeared. The cells of the leaf blade are prosenchymatic, many times longer than wide, with pointed ends interlocking. The sporophyte consists of a regularly shaped sporangium on a long stalk or seta. The spores are distributed via a ring-shaped opening with two rows of teeth, the peristome, which before ripeness is closed by a beak-shaped operculum.
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Isoetes riparia, the shore quillwort, is a species of plant in the family Isoetaceae. It can be found in rivers, creeks, and tidal mud flats in southern Quebec and southeastern Ontario, south to eastern New York. It has 5 to 35 long, erect bright green to yellow-green leaves, which are 6 to 35 centimeters long. The velum covers one fourth of the sporangium, which can be 7 millimeters long and 4 millimeters wide.
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Zygote fungus sporangium, with columella labelled Columella (in plants) is an axis of sterile tissue which passes through the center of the spore-case of mosses. In fungi it refers to a centrally vacuolated part of a hypha, bearing spores. The word finds analogous usage in myxomycetes. The term columella is also used to refer to story 1 to story 4 (S1 – S4) cells in the root cap located apically of the quiescent centre.
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These motile spores will move on to infect a root in the soil. Throughout the season if conditions are warm and wet enough the sporangium will continue to make more zoospores which can go no to infect other roots. It is within an infected root that additional oospores will be produced to overwinter another season. Although disease develops in less heavy soils, a heavy textured soil is favorable as they tend to remain wetter.
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The first stage in the Peronospora life history is the sporangia. The sporangia are small spore-like structures about 65 um long that germinate a germ-tube when they are near a leaf stoma. A germ tube will come from the sporangium and penetrate the leaf cell where it will form a haustorium. The haustorium absorbs nutrients from the leaf, while hyphae invade the intercellular space, and the leaf will eventually develop a lesion.
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Argyrochosma jonesii, with the common name is Jones' false cloak fern, is a species of fern native to the southwestern United States and northern Mexico. It grows in cracks in calcareous ledges and slopes in and around the Mojave and Sonoran Deserts. This fern produces leaves up to 15 centimeters long which are made up of leaflets subdivided into leathery, fleshy segments which are rounded to spade-shaped. Each sporangium contains 64 spores.
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Sporangia were arranged in four rows, two sporangia being opposite to one another on the stem with the next two being at right angles. Each sporangium consisted of two 'valves' which opened at the top to release their spores. A particular feature of Demersatheca which distinguishes it from other zosterophylls is that the stalk-less sporangia were sunken into the stem of the spike, so that the outer valve was flush with the surface.
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On fertile fronds, the sori are protected by false indusia formed by the edge of the leaf curling back over the underside. The false indusia look similar, though not identical, to the rest of the leaf tissue, and are 0.05–0.25 mm wide. Beneath them, the sori do not form long lines, but are discontinuous and concentrated on lobes at the tip and sides of the pinnule. Each sporangium in a sorus carries 64 spores.
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Among them, Bowmanites or Sphenophyllostachys have variously constructed bracts adaxially attached by a variable number of sporangiophores with anatropous or orthotropous terminal sporangia (Good, 1978). Each bract of the Sphenostrobus strobilus has a single axillary sporangiophore ending in one sporangium (Levittan & Barghoorn, 1948; Good, 1978). In Peltastrobus (Leisman & Graves, 1964), the more complex strobilus consists of a whorl of three sterile and three fertile units at each node. Sterile and fertile units alternate.
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Between species of Ulota, there is variation in the length of the seta which can be a useful trait in classifying species. The sporangia have peristome teeth are diplolepidous, with 8 to 16 exostome teeth and 8 endostome teeth. The sporangia sit on top of a seta which attaches to the gametophyte at the apex of the shoot. The calyptra covers the developing sporangium and is typically conic, split at the base, and can be naked or hairy.
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Further, the axis thickness is what would be expected if its sole role was to support a sporangium. It appears that, originally at least, the role of the axes in smaller species was solely to ensure continued spore dispersal, even if the axis desiccated. The potential self-sufficiency of the larger axes may represent the evolution of an independent sporophyte generation. In 2018, the sporophyte of a new species, Cooksonia barrandei, was described, from about 432 million years ago.
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Above this is a shorter "urn" which is the same colour, and harbours a bluntly conical or convex operculum on top; of which the annulus is poorly developed. A single peristome is present, with 16 variably pigmented teeth (exostome usually consists of 8 teeth). Stomata are often abundant on the sporangium. A haploid calyptra, composed of tissue from the gametophyte, may be present on the sporophyte; it being nearly always mitrate (shaped like a bishop's cap) and smooth.
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The species most similar to A. × ebenoides is A. tutwilerae, long considered conspecific and only found at Havana Glen, Alabama. The two may be distinguished by their spores; A. tutwilerae bears sixty-four well-formed spores per sporangium, while those of A. × ebenoides are sterile and malformed. In the wild, A. × ebenoides is most likely to be confused with A. pinnatifidum, which also has a long, lobed blade. Nonetheless, there are several marked characters that distinguish them.
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Lemmermannia perform asexual reproduction (autosporation by sporangium); sexual reproduction has not been observed. Lemmermannia species perform two types of reproduction: L. tetrapedia exhibits Crucigenia-type of autosporation where the daughter coenobium rotates 45˚ relative to the cell wall of the mother coenobium; the other four species produce daughter coenobia in the same orientation as the mother coenobia. This demonstrates that in this taxon a Crucigenia-type of autosporation should not be used as a generic character.
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Fungal transmission occurs through the movement of microscopic reproductive spores through the environment. These spores are released out into the environment via the rupturing of a sporangium. Once the release of spores occurs, their movement is dependent on environmental conditions, more specially, being blown through wind, passing through water streams etc. Spores will continue to travel through the environment until they come in contact with an insect where the organism will become infected, and the pathogen’s life cycle will begin.
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Hypnum lindbergii, cross section of the stem with the central vascular bundle leaf blade cells Detail of a sporangium with a beak-shaped operculum Hypnales are mosses with pinnately or irregularly branched, reclining stems, with varying appearances. The stem contains only a reduced central vascular bundle, which is seen as a recent derived trait in mosses. The stems are covered with paraphyllia or pseudoparaphyllia, reduced filamentous or scaly leaves. The ordinary stem leaves are ovate to lanceolate, often with leaf wing cells.
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Isoetes tuckermanii, or Tuckerman's quillwort, is a tetraploid species of plant in the family Isoetaceae. It can be found in shallow water in Newfoundland, Nova Scotia, New Brunswick, and south through the New England states to Maryland. It bears 10 to 45 long bright green to yellow green leaves that are 4 to 25 centimeters long, usually erect, but sometimes recurved. The velum covers one fourth or less of the sporangium, which is usually unspotted, 5 millimeters long, and 3 millimeters wide.
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Rhizopus soft rot produces a characteristic fermentation odor. Roots may dry and mummify with only the periderm and root fibers remaining intact because of the inability of the fungus to break down the lignin in these components. Characteristic signs of Rhizopus soft rot include the production of tufts of white hyphae which break through the surface of the root and produce large numbers of brown-black sporangiophores (34 µm diam. by 1000-3500 µm length) which support a sporangium (100-350 µm diam.).
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After several steps of differentiation and meiosis, an oospore, the primary survival structure, is formed. These thick-walled oospores can remain dormant for many months, and will eventually germinate through two methods. A sporangium can be produced, which generates a cyst and releases zoospores, or the oospore can create a germ tube which can directly penetrate and infect a host. This disease cycle is extremely dependent on water for dispersal, making greenhouses, irrigation systems, and hydroponics especially prone to spread of P. dissotocum.
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They always have unbranched hairs, while many species have branched hairs with a single gland at the apex. Some species have hydathodes, some of which are cretaceous (leaving a lime deposit on the leaf around them). The sporangia bear one to two (occasionally as many as six) stiff, simple straight hairs without glands at the tip of the sporangium. Parris observed that the genus resembles Prosaptia in bearing phyllopodia at the stipe bases, but lacks the clathrate rhizome scales of that genus.
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Transitional fossils are not only those of animals. With the increasing mapping of the divisions of plants at the beginning of the 20th century, the search began for the ancestor of the vascular plants. In 1917, Robert Kidston and William Henry Lang found the remains of an extremely primitive plant in the Rhynie chert in Aberdeenshire, Scotland, and named it Rhynia. The Rhynia plant was small and stick-like, with simple dichotomously branching stems without leaves, each tipped by a sporangium.
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Cunninghamella echinulata is a member of the family, Cunninghamellaceae (phylum Mucoromycota). This species is closely related to C. elegans, and both species share highly similar characteristics of growth and morphology. Colonies tend to be rapidly growing on most growth media producing a dense, white or greyish aerial mycelium. Cunninghamella echinulata reproduces asexually and solely via yellow-brown, spiny, single-spored sporangioles that, due to the nature of the sporangiospore being retained within the sporangium, appear to have a two- layered outer wall.
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A unique feature of this genus among plants of similar age is the manner in which the sporangia (spore-forming organs) were borne. Fertile stems had terminal 'strobili', structures very superficially resembling an ear of wheat, which consisted of four vertical rows of fan- shaped leaf-like organs (sporophylls), each with a stalked sporangium on the side facing the stem (adaxial). The flattened sporangia were almost round and split (dehisced) along a distally thickened margin into two equal parts. The sporophylls may have had vascular tissue.
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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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In heterosporous plants (water ferns, some lycophytes, as well as all gymnosperms and angiosperms), there are two distinct sporangia, each of which produces a single kind of spore and single kind of gametophyte. However, not all heteromorphic gametophytes come from heterosporous plants. That is, some plants have distinct egg-producing and sperm-producing gametophytes, but these gametophytes develop from the same kind of spore inside the same sporangium; Sphaerocarpos is an example of such a plant. In seed plants, the microgametophyte is called pollen.
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The genus Labyrinthula is part of the group Labyrinthulomycetes and contains thirteen species. The major feature of this genus is the formation of an ectoplasmic net secreted by specialized organelles called bothrosomes which surrounds the colony, which is also used by Labyrinthula for moving. The protist reproduces by zoosporulation as it sets some flagellated spores free from a sporangium. Zoospores prove the belonging of Labyrinthula in the Heterokont phylum due to the distinct flagellar morphology, in which the anterior one is covered in mastigonemes.
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Pilobolus species can be grown in artificial culture, but only when the growth medium is supplemented with some form of chelated iron, or with sterilized herbivore dung. The forcible discharge mechanism of Pilobolus is exploited by parasitic nematodes including lungworms in the genus Dictyocaulus. Larval lungworm nematodes excreted by infected deer, elk, cattle, horses, and other hosts climb up Pilobolus sporangiophores and are discharged with the sporangium. They complete their life cycle when they and their Pilobolus vector are eaten by a new host.
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Among the Bryopsida, the structure of the capsule (sporangium) and its pattern of development is very useful both for classifying and for identifying moss families. Most Bryopsida produce a capsule with a lid (the operculum) which falls off when the spores inside are mature and thus ready to be dispersed. The opening thus revealed is called the stoma (meaning "mouth") and is surrounded by one or two peristomes. A peristome is a ring of triangular "teeth" formed from the remnants of specially thickened cell walls.
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The organisms probably exhibited determinate growth (i.e. stems did not grow further after producing sporangia). Some Cooksonia species bore stomata, which had a role in gas exchange; this was probably to assist in transpiration-driven transport of dissolved materials in the xylem, rather than primarily in photosynthesis, as suggested by their concentration at the tips of the axes. These clusterings of stomata are typically associated with a bulging in the axis at the neck of the sporangium, which may have contained photosynthetic tissue, reminiscent of some mosses.
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The release of the zoospores occurring through a germ tube is a characteristic that is shared with the Perkinsus taxa (Reñé et al. 2017). One other difference is that the sporangium wall is found to be smooth in P.prorocentri. In retrospect of all these differing characteristics of P.prorocentri may indicate that it belongs to a different genus, although it is too early to make this claim prior to the lack of discovery of more Parvilucifera species that may also have germ tube release (Reñé et al. 2017).
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The sporocarps are functionally and developmentally modified leaflets, although they have much shorter stalks than the vegetative leaflets. Inside the sporocarp, the modified leaflets bear several sori, each of which consists of several sporangia covered by a thin hood of tissue (the indusium). Each sorus includes a mix of two types of sporangium, each type producing only one of two kinds of spores. Toward the center of each sorus and developing first are the megasporangia, each of which will produce a single large female megaspore.
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Hemitricha is a genus of slime molds, of the family Trichiidae, found within the order Trichiida. It was first described by Josef Rostafinksi in 1873 and remains a well-defined genus of the slime molds. Hemitrichia species exhibit either plasmodiocarp or sporangium fruiting bodies, both of which are well- known and recognizable slime molds seen on multiple continents. The genus includes Hemtrichia serpula, known as the pretzel slime mold, an iconic and widespread species that has been used to examine speciation in slime molds.
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The layers appear separated into two 'valves' in some specimens. Cai et al. say that it is difficult to reconstruct the three-dimensional structure of a sporangium before preservation; it may have been more-or-less spherical or it may already have been compressed from side to side before being fossilized. They concluded that "[t]hese unique and somewhat bizarre sporangia ... defy our understanding", but that the most surprising feature was their complexity relative to other Silurian species such as Salopella, Cooksonia or Steganotheca.
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Barinophyton is the type genus of the group; Protobarinophyton is similar. They were vascular plants with an exarch protostele. Plants consisted of alternatively arranged branches, apparently without leaves or enations, with their sporangia arranged in two rows on one-sided spike-like structures that developed on side shoots. Each sporangium was born on a curved bract-like appendage (a "sporangiferous appendage") and contained several thousand microspores, about 30–40 µm in diameter and about 30 megaspores, 410–560 µm in diameter, so that the plants were heterosporous.
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In some cases, both kinds of spores are produced in the same sporangium, and may even develop together as part of a spore tetrad. However, in most heterosporous plants there are two kinds of sporangia, termed microsporangia and megasporangia. A few ferns (Salviniaceae and Marsileaceae) and some lycophytes (the genera Selaginella and Isoetes and the extinct lepidodendrids) are heterosporous with two kinds of sporangia, as are all the seed plants. Sporangia can be terminal (on the tips) or lateral (placed along the side) of stems or associated with leaves.
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New species and genera are still being discovered in this order. A member of this order, Kappamyces, was the first phylogenetic genus of a chytrid circumscribed based primarily on monophyly demonstrated in molecular sequence analysis and confirmed with unique zoospore structure Coralloidiomyces digitatus defied the original view held that the thallus of members of the Rhizophydiales was conservative. Collected from submersed mud at the edge of an oligotrophic lake in southern Argentina near the Andes in Patagonia, C. digitatus has a thallus with a sporangium shaped like a coral.
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Seed plant microgametophytes consists of several (typically two to five) cells when the pollen grains exit the sporangium. The megagametophyte develops within the megaspore of extant seedless vascular plants and within the megasporangium in a cone or flower in seed plants. In seed plants, the microgametophyte (pollen) travels to the vicinity of the egg cell (carried by a physical or animal vector), and produces two sperm by mitosis. In gymnosperms the megagametophyte consists of several thousand cells and produces one to several archegonia, each with a single egg cell.
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In endosporic species, the gametophytes of both sexes are very highly reduced and contained within the spore wall. The microspores of both exosporic and endosporic species are free-sporing, distributed by wind, water or animal vectors, but in endosporic species the megaspores and the megagametophyte contained within are retained and nurtured by the sporophyte phase. Endosporic species are thus usually dioecious, a condition that promotes outcrossing. Some exosporic species produce micro- and megaspores in the same sporangium, a condition known as homoangy, while in others the micro- and megaspores are produced in separate sporangia (heterangy).
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The species was originally named Marchantia tenerum by Hooker, but later placed in the genus Cryptomitrium by Austin before being revised into its current description by Underwood in 1884. The genus Cryptomitrium is placed in the Aytoniaceae with other liverworts with flat thalli and stalked receptacles, such as Asterella, The genus name means “hidden turban” in reference to the inconspicuous sheath around the immature sporangium. The common name for Cryptomitrium tenerum is the flying saucer liverwort referring to the flat disc-shaped sporangiophore perched on a tall thin stalk.
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They had a simple stalk that branched dichotomously a few times. Each branch ended in a sporangium or spore-bearing capsule. In his original description of the genus, Lang described the sporangia as flattened, "with terminal sporangia that are short and wide", and in the species Cooksonia pertoni "considerably wider than high". A 2010 review of the genus by Gonez and Gerrienne produced a tighter definition, which requires the sporangia to be more-or-less trumpet-shaped (as in the illustration), with a 'lid' or operculum which disintegrates to release the spores.
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This dehiscence causes the cells to shrink and a contraction and straightening of the annulus ring, eventually rupturing the sporangial wall by ripping apart thin-walled lip cells on the opposite side of the sporangium. As more water evaporates, air bubbles form in the cells causing the contracted annulus to snap forward again, thus dislodging and launching the spores away from the plant. The type and position of the annulus is variable (e.g. patch, apical, oblique, or vertical) and can be used to distinguish major groups of leptosporangiate ferns.
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Thus far, five species have been described in this taxon, which include: P.infectans, P.sinerae, P.corolla, P.rostrata, and P.prorocentri. The genus Parvilucifera is morphologically characterized by flagellated zoospore. The life cycle of the species in this genus consist of free-living zoospores, an intracellular stage called trophont, and asexual division to form resting sporangium inside host cell. This taxon has gained more interest in research due to its potential significance in terms of negative regulation for dinoflagellates blooms, that have proved harmful for algal species, humans, and the shellfish industry (Norén et al. 1999).
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The ciliate family Grossglockneridae, including the species Grossglockneria acuta, feed exclusively on fungi. G. acuta first attaches themselves to a hyphae or sporangium via a feeding tube and then a ring-shaped structure, around 2 μm in diameter is observed to appear on the fungus, possibly consisting of degraded cell wall material. G. acuta then feeds through the hole in the cell wall for, on average, 10 minutes, before detaching itself and moving away. The precise mechanism of feeding is not known, but it conceivably involves enzymes including acid phosphatases, cellulases and chitinases.
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The sporangium capsule is very tiny 0.6-1 mm long that is erect or sometimes lightly curved, resembling a shape of an ellipsoid. The immature capsule of F.limbatus is green, and the operculum is fully and prominently enlarged above the annulus. The tip of the operculum is somewhat clear-green in colour. The capsule turns dark green to brown when maturing, except for the apophysis, keeps it light green colour and the operculum that turns red as each sporocyte has experienced meiosis and has produced four spores at this time.
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It contains 64 spores per sporangium, and most sporophytes have a chromosome number of 2n=144 (a tetraploid). Fertile leaves of A. septentrionale showing brown sori on underside Individual plants have an abundant number of leaves, forming dense tufts from a rhizome of about 1 millimetre in diameter, and sometimes mats on flat rocks. A. septentrionale is easily distinguished from other related ferns by its narrow blades, often forked at the tip. The presence of sori on fertile leaves distinguishes it from the vegetative material of a grass or sedge.
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Zosterophyllum fossils from North Rhine-Westphalia; left: showing curled (circinnate) branch tip; right: with sporangium The diagnostic features of the genus have changed since its first description in 1892, as the original species (Zosterophyllum myretonianum) has become better known, and as other species have been discovered. Zosterophyllum is a vascular plant. The axes (stems) are naked, lacking leaves or outgrowths ("enations"). When branching occurs, the branches are either isotomous (equally sized) or pseudomonopodial (one branch is larger than the other but still clearly involves division of the original axis rather a distinct side growth).
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Unlike most species of Phytophthora, which are diploid, P. alni alni is near tetraploid and unable to complete meiosis beyond metaphase I. In culture, many oogonia prematurely abort or appear abnormal and only one third of the oospores that appear normal are reported to be viable. As a result, it is believed to spread predominantly via asexual means, namely zoospores which are produced in a specialised structure known as the sporangium. Water temperature has been shown to affect sporulation, with warmer water increasing sporangia production. Temperatures of 8 °C and below prevent production of sporangia.
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Each sporangium bears 64 spores. The plants are diploid, with a chromosome number of 2n = 54. Within the heart of its range, in Mexico, A. incana is both the most widespread member of the genus and the most variable. Some of the characteristics observed to vary are the size of segments (reduced to wide), the density of adaxial farina, the shape and color of the blade axes (zigzag rather than straight, and dark purplish rather than black), and the joint at the base of leaf segments (more sharply defined).
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As to Hamatophyton, each sporangiophore at the strobilar node bifurcates into two parts. The shorter part acts as a possible bract, the longer one results in two adaxially recurved long stalks, each of which terminates in an elliptical sporangium. Two sporangia are more or less parallel to the sporangiophore before bifurcation. In Rotafolia, however, each fertile unit of the strobilus has an elongate-cuneate bract that bears a distal segment and 10–18 lateral elongate segments. 6–10 elongate abaxial sporangia are pendulous at the base of the bract.
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S. huangkuangensis, S. songziensis, S. oblongifolius, S. sp.1 and S. sp.2. Generally speaking, these taxa were regarded as possessing fertile axes with nodes and internodes, whorls of bracts that are decurrent and terminally curved towards the strobilar axis or occasionally bifurcate at tips; each bract has one or two variously shaped adaxial sporangia with a short stalk. One noticeable character is the so- called ‘lines of ornamentation on the surface of the sporangium’ in some species. Feng & Ma also suggested that the reproductive organ of Hamatophyton Gu & Zhi, 1974 be replaced by Sphenophyllostachys.
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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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Pogonatum urnigerum has leaves that grow in more than three rows around its stem which makes the plant appear robust, its leaves and branches do not appear to be flat, it has a midrib, it lacks structures that produce gemmae, its sporangium has thirty-two nematodontous teeth, the bordering cells of the leaves do not differ from the rest of the leaf, white hair points and wrinkles on the ventral side of leaves are absent, numerous lamellae are present on the ventral surface, marginal teeth are present, and the plant may look bluish-green when it is not dry.
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The Marattiaceae diverged from other ferns very early in their evolutionary history and are quite different from many plants familiar to people in temperate zones. Many of them have massive, fleshy rootstocks and the largest known fronds of any fern. The Marattiaceae is one of two groups of ferns traditionally known as eusporangiate ferns, meaning that the sporangium is formed from a group of cells as opposed to a leptosporangium in which there is a single initial cell. The large fronds characteristic of the group are most readily found in the genus Angiopteris, native to Australasia, Madagascar and Oceania.
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The oocytes were fertilized in the archegonia by free-swimming flagellate sperm produced by windborne miniaturized male gametophytes in the form of pre-pollen. The resulting zygote developed into the next sporophyte generation while still retained within the pre-ovule, the single large female meiospore or megaspore contained in the modified sporangium or nucellus of the parent sporophyte. The evolution of heterospory and endospory were among the earliest steps in the evolution of seeds of the kind produced by gymnosperms and angiosperms today. The rRNA genes seems to escape global methylation machinery in bryophytes, unlike seed plants.
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Tortilicaulis is a moss-like plant known from fossils recovered from southern Britain, spanning the Silurian-Devonian boundary (around ). Originally recovered from the Downtonian of the Welsh borderlands, Tortilicaulis has since been recovered in the famous Ludlow Lane locality. Whilst it is generally accepted that Tortilicaulis was moss-like, it has not yet been recovered in a sufficiently good state of preservation to allow the detailed study necessary to firmly assign it to a taxonomic group. Fossils consist of an elongate apical sporangium (spore-forming organ), which may be branched, with spiralled walls attached to an undivided stalk that is also twisted.
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In the spring the oospores germinate and produce sporangia on short stalks called sporangiophores that become so tightly packed within the leaf that they rupture the epidermis and are consequently spread by the wind. The liberated sporangia in turn can either germinate directly with a germ tube or begin to produce biflagellate motile zoospores. These zoospores then swim in a film of water to a suitable site and each one produces a germ tube - like that of the sporangium - that penetrates the stoma. When the oomycete has successfully invaded the host plant, it grows and continues to reproduce.
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Arthrodontous capsule of the moss Dicranella varia Peristoma of Bryum capillare In mosses, the peristome is a specialized structure in the sporangium that allows for gradual spore discharge, instead of releasing them all at once. Most mosses produce a capsule with a lid (the operculum) which falls off when the spores inside are mature and thus ready to be dispersed. The opening thus revealed is called the stoma (meaning "mouth") and is surrounded by one or two peristomes. Each peristome is a ring of triangular "teeth" formed from the remnants of dead cells with thickened cell walls.
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The dimorphic form of the species mainly exists and grows vegetatively as either a filamentous hyphae (mould form) or as spherical yeast (yeast form). However, the organism is best known from the mould form which is characterised by the production of asexual reproductive state consisting of tall (up to 2 cm) needle-like sporangiophores with an apical swelling enclosed by a large sporangium filled with ellipsoidal, single-celled, smooth-walled, unpigmented sporangiospores. In the laboratory, the fungus forms dark grey or light grey colonies on most common laboratory media. If subjected to anaerobic conditions, the fungus may convert to the yeast-like form.
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Saksenaea vasiformis very rapidly grows in growth media, producing sterile hyphae. Induction of sporulation is difficult with routine fungal media used in the most of clinical laboratories, but it can be stimulated to sporulate rapidly (5 to 7 days) by incubating the yeast-malt-dextrose agar at 32 °C. The identification of this species is not problematic after sporulation event because of its characteristic flask-shaped sporangium with spherical venter and a distinct dome-shped columella and dichotomously branched rhizoid complex. On top of the venter, there is a neck with closed apex with a mucilaginous plug.
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His most outstanding efforts went into the study of the Cryptonmeiales and the Gigartinales. He established the family Corynomorphaceae and created two new genera, Isabottia and Norrisia. His work on Batrachospermum and Sirodotia of the Batrachospermales, established the existence of a heteromorphic alternation of generations, the sporophyte being filamentous and bearing a highly modified type of sporangium involving the formation of elimination cells during a modified meiotic process. His intensive taxonomic studies on the red algae culminated in the preparation of a book on the Indian Rhodophyta along with his close associates Professors T.V.Desikachary V. Krishnamurthy.
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Young sporophytes of the common moss Tortula muralis. In mosses, the gametophyte is the dominant generation, while the sporophytes consist of sporangium-bearing stalks growing from the tips of the gametophytes Sporophytes of moss during spring A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga. It develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent. All land plants, and most multicellular algae, have life cycles in which a multicellular diploid sporophyte phase alternates with a multicellular haploid gametophyte phase.
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Spinellus fusiger, commonly known as the bonnet mold, is a species of fungus in the Zygomycota phylum. It is a pin mold that is characterized by erect sporangiophores (specialized hyphae that bear a sporangium) that are simple in structure, brown or yellowish-brown in color, and with branched aerial filaments that bear the zygospores. It grows as a parasitic mold on mushrooms, including several species from the genera Mycena, including M. haematopus, M. pura, M. epipterygia, M. leptocephala, and various Collybia species, such as C. alkalivirens, C. luteifolia, C. dryophila, and C. butyracea. It has also been found growing on agaric species in Amanita, Gymnopus, and Hygrophorus.
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27 Page 102, Andreaea Hedwig They are small, delicate acrocarpous mosses (meaning that the capsules are formed at the tips of vertical branches) that form dark brown or reddish cushions on wet siliceous rocks in mountainous areas. The capsule lacks the peristome teeth and operculum of other mosses, and opens by splitting along 4 vertical slits, the four valves remaining joined at the base and apex. The capsule of Andreaea has no seta, but the sporophyte (Spf in the diagram below) instead is supported by a pseudopodium (ps) derived from gametophyte tissue, as in Sphagnum and the columella is enclosed within the sporangium. The spores germinate to give thalloid protonemata.
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Marchantiales is an order of thallose liverworts that includes species like Marchantia polymorpha, a widespread plant often found beside rivers, and Lunularia cruciata, a common and often troublesome weed in moist, temperate gardens and greenhouses. As in other bryophytes, the gametophyte generation is dominant, with the sporophyte existing as a short-lived part of the life cycle, dependent upon the gametophyte. The genus Marchantia is often used to typify the order, although there are also many species of Asterella and species of the genus Riccia are more numerous. The majority of genera are characterized by the presence of (a) special stalked vertical branches called archegoniophores or carocephala, and (b) sterile cells celled elaters inside the sporangium.
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It is widely accepted that no single English word is a full rhyme for orange, though there are half rhymes, such as hinge, lozenge, syringe, and porridge. Although this property is not unique to the word—one study of 5,411 one-syllable English words found 80 words with no rhymes—the lack of rhyme for orange has garnered significant attention, and inspired many humorous verses. Although sporange, a variant of sporangium, is an eye rhyme for orange, it is not a true rhyme as its second syllable is pronounced with an unreduced vowel , and often stressed. There are a number of proper nouns which rhyme or nearly rhyme with orange, including The Blorenge, a mountain in Wales, and Gorringe, a surname.
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Lemon-shaped sporangia of Plasmopara viticola Sporangium and spores of Plasmopara viticola The disease development of grape downy mildew is known to be heavily reliant on the efficiency of the asexual propagation cycles. Kiefer et al. (2002) demonstrated that the early development of Plasmopara viticola is regulated specifically and coordinately by unknown factors originating from the host grapevine plant Vitis vinifera. The host factors influence the pathogen development in three ways: (i) accelerating the release of zoospores from mature sporangia, (ii) coordinating the morphogenesis of the germ tube through the reorientation of the polarity of the zoospores during the attachment to the host cell, and (iii) targeting the zoospores to the stomata by active chemotaxis from the open substomatal cavity.
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In damp weather, a Polysphondylium pallidum myxamoeba can move around at a speed of about per hour, leaving a chemical trail behind it. When it finds the trail left by another myxamoeba, it follows it, superimposing its own trace signal, and more and more individuals collect together in this way. Under favourable conditions, the myxamoebae agglutinate and stick together to form a "pseudoplasmodium" in which they remain separate individuals but behave as if the whole mass was a single organism. The pseudoplasmodium can move around and in due course develops into a fruiting body called a sporangium, about a third of the cells forming a stalk and the remaining cells forming a ball at the top where they develop into spores.
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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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There are some characteristics that are found in P. corolla, P.infectans, P.sinerae, and P.rostrata that are not found in P.prorocentri include a dense globule in the basal body, dense area in the axoneme and a residual body inside the sporangium. The species P.prorocentri has had a lot of uncertainty around whether or not it has been placed in the correct clade due to its overlap of characteristics with Perkinsids (Hoppenrath & Leander 2009). The following morphological characteristics are found in P.prorocentric species that are not found in other Parvilucifera species: a germ tube, bipartile trichocysts, and syndinean-like nucleus (Reñé et al. 2017). The germ tube is the pathway through which the zoospores are released in P.proroccentri, in contrast to the release through apertures of the operculum such as the other Parvilucifera species (Hoppenrath & Leander 2009).
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While the fossil record of crown group hornworts only begins in the upper Cretaceous, the lower Devonian Horneophyton may represent a stem group to the clade, as it possesses a sporangium with central columella not attached at the roof. However, the same form of columella is also characteristic of basal moss groups, such as the Sphagnopsida and Andreaeopsida, and has been interpreted as a character common to all early land plants with stomata. Chromosome-scale genome sequencing of three hornwort species corroborate that stomata evolved only once during land plant evolution. It also shows that the three groups of bryophytes share a common ancestor that branched off from the other landplants early in evolution, and that liverworts and mosses are more closely related to each other than with hornworts.
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Lepidodendrales (from the Greek for "scale tree") were primitive, vascular, arborescent (tree-like) plants related to the lycopsids (club mosses). Members of Lepidodendrales are the best understood of the fossil lycopsids due to the vast diversity of Lepidodendrales specimens and the diversity in which they were preserved; the extensive distribution of Lepidodendrales specimens as well as their well-preservedness lends paleobotanists exceptionally detailed knowledge of the coal-swamp giants’ reproductive biology, vegetative development, and role in their paleoecosystem. The defining characteristics of the Lepidodendrales are their secondary xylem, extensive periderm development, three-zoned cortex, rootlike appendages known as stigmarian rootlets arranged in a spiralling pattern, and megasporangium each containing a single functional megaspore that germinates inside the sporangium. Many of these different plant organs have been assigned both generic and specific names as relatively few have been found organically attached to each other.
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It is a commonplace that plant development is not reversible in time. For example, two daughter cells never go through a reverse mitosis to merge into one mother cell; four pollen grains never go through a reverse meiosis to merge into a pollen mother cell; ejected fern spores never reassemble in a sporangium; and oak trees never recede into an acorn. The irreversibility of plant development is inconsistent with the fundamental laws of physics, which are symmetrical with respect to time and predict that all events are fundamentally reversible. Wayne has shown that the inconsistency between the botanical view and the physical view is a result of temperature being an outsider in the laws of motion given by Newton and Einstein and that this oversight is the source of the predictions of time-reversal-invariance (TRI) or T-symmetry made by these two great systems of motion.
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He moved to study at the Jodrell Laboratory on a Robert Donaldson scholarship in 1895, where he focused on the apomixis of ferns, and discovered a sporangium on the prothallus of a fern at a time when biologists were exploring alternate means of reproduction in plants. In 1899 he travelled to Sri Lanka and Malaya to study tropical cryptogams and collect samples, returning to Britain in 1902, when he became a lecturer at the University of Glasgow; while there he worked closely with D. T. Gwynne-Vaughan and Bower, with the three of them being known as the "triumvirate". After Gwynne- Vaughan's death in 1915 he studied preserved plant remnants in Aberdeen, making great insights into the nature of Psilophyton, which until then had been neglected. In 1900 he was awarded a Doctor of Science degree by the University of Glasgow, and when the Barker chair of cryptogamic botany was created at the University of Manchester Lang was the first choice.
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