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Strobile
A strobilus (: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis (anatomically a stem) surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems. Leaves that bear sporangia are called ''sporophylls'', while sporangia-bearing stems are called ''sporangiophores''. Lycophytes Some members of both of the two modern classes of Lycopodiophyta (Lycopodiopsida and Isoetopsida) produce strobili. In all cases, the lateral organs of the strobilus are microphylls, bearing sporangia. In other lycophytes, ordinary foliage leaves can act as sporophylls, and there are no organized strobili. Diphasiastrum complanatum strobilus (01).jpeg, Strobili of ''Diphasiastrum'' Lycopodium saururus.JPG, Strobili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetophyta
Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: '' Gnetum'' (family Gnetaceae), '' Welwitschia'' (family Welwitschiaceae), and '' Ephedra'' (family Ephedraceae). The earliest unambiguous records of the group date to the Jurassic, and they achieved their highest diversity during the Early Cretaceous. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of small tubes (xylem) that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question, with many recent phylogenies finding them to be nested within the conifers. Though it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cestode
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, commonly known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish-infecting parasites. All cestodes are parasitic; many have complex life histories, including a stage in a definitive (main) host in which the adults grow and reproduce, often for years, and one or two intermediate stages in which the larvae develop in other hosts. Typically the adults live in the digestive tracts of vertebrates, while the larvae often live in the bodies of other animals, either vertebrates or invertebrates. For example, '' Diphyllobothrium'' has at least two intermediate hosts, a crustacean and then one or mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equisetum
''Equisetum'' (; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass Equisetidae, which for over 100 million years was much more diverse and dominated the understorey of late Paleozoic forests. Some equisetids were large trees reaching to tall. The genus ''Calamites'' of the family Calamitaceae, for example, is abundant in coal deposits from the Carboniferous period. The pattern of spacing of nodes in horsetails, wherein those toward the apex of the shoot are increasingly close together, is said to have inspired John Napier to invent logarithms. Modern horsetails first appeared during the Jurassic period. A superficially similar but entirely unrelated flowering plant genus, mare's tail (''Hippuris''), is occasionally referred to as "horsetail", and adding to confusion, the name "mare's tail" is sometimes applied to ''Equis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welwitschia
''Welwitschia'' is a monotypic genus of gnetophytes containing only the species ''Welwitschia mirabilis''. It is named after the Austrian botanist Friedrich Welwitsch, who documented the plant in the 1850s. In common use, it is sometimes referred to as the tree tumbo. It is native to Angola and Namibia, where it grows in the extreme conditions of the Namib desert, tolerating high heat and low precipitation. ''Welwitschia'' is the only living genus of the family Welwitschiaceae and order Welwitschiales, and is one of three extant genera of gnetophytes, alongside '' Gnetum'' and '' Ephedra''. ''Welwitschia'' is well known for its unique morphology. The plant only has two leaves that grow out of a large woody stem, dubbed a crown, and continue to grow over the plant's entire life. ''Welwitschia'' is one of the longest-living plants on Earth, with some individuals being thousands of years old. As such, the leaves can become quite large, often reaching several meters in length. L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetum
''Gnetum'' is a genus of gymnosperms, the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpionflies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the ''Gnetum'' lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater. Their leaves are rich in phytochemicals such as flavonoids and stilbenes. Of the species studied so far, ''Gnetum'' have photosynthetic and transpiration capacities which are considerably lower than those of other seed plants, due to the absence of multiple c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ephedra (genus)
''Ephedra'' is a genus of gymnosperm shrubs. there were 77 recognized species. The various species of ''Ephedra'' are widespread in many arid regions of the world, ranging across southwestern North America, southern Europe, northern Africa, southwest and central Asia, northern China, and western South America. It is the only extant genus in its family, Ephedraceae, and order, Ephedrales, and one of the three living members of the division Gnetophyta alongside '' Gnetum'' and '' Welwitschia.'' In temperate climates, most ''Ephedra'' species grow on shores or in sandy soils with direct sun exposure. Common names in English include joint-pine, jointfir, Mormon-tea, or Brigham tea. The Chinese name for ''Ephedra'' species is ''mahuang'' (). ''Ephedra'' is the origin of the name of the stimulant ephedrine, which the plants contain in significant concentration. Description The family Ephedraceae, of which ''Ephedra'' is the only extant genus, are gymnosperms, and generally shr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinophyta
Conifers () are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.Campbell, Reece, "Phylum Coniferophyta". ''Biology''. 7th ed. 2005. Print. p. 595. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adapta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ginkgo Biloba
''Ginkgo biloba'', commonly known as ginkgo or gingko ( ), also known as the maidenhair tree, is a species of gymnosperm tree native to East Asia. It is the last living species in the order Ginkgoales, which first appeared over 290 million years ago. Fossil, Fossils very similar to the living species, belonging to the genus ''Ginkgo'', extend back to the Middle Jurassic epoch approximately 170 million years ago. The tree was cultivated early in human history, remains commonly planted, and is widely regarded as a living fossil. ''G. biloba'' is a long-lived, Disease resistance, disease-resistant, Dioecy, dioecious tree with unique fan-shaped Leaf, leaves, capable of Cloning, clonal reproduction, and known for its striking yellow autumn foliage and resilience in disturbed environments. It was known historically as “silver fruit” or “white fruit” in Chinese language, Chinese and called “ginkgo” due to a centuries-old transcription error. It is closely related to Cycad, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ginkgophyta
Ginkgoopsida is a proposed class of gymnosperms defined by Sergei V. Meyen in 1984 to encompass Ginkgoales (which contains the living ''Ginkgo'') alongside a number of extinct seed plant groups, which he considered to be closely related based on similarities of morphology of pollen, seeds, cuticles, short shoots and leaves. The validity of this group as a whole has been considered questionable by other authors, who consider that it is unlikely to be monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co .... Other authors have used the class as a monotypic grouping, including only Ginkgoales. Some authors have used the clade Ginkgophyta to encompass both Ginkgoales and Czekanowskiales/Leptostrobales, which are suggested to be closely related groups. References {{Taxonbar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycas Revoluta
''Cycas revoluta'' (Sotetsu apanese ソテツ sago cycad, sago palm, king sago, Japanese sago palm) is a species of gymnosperm in the family Cycadaceae, native to southern Japan including the Ryukyu Islands. It is one of several species used for the production of sago, as well as an ornamental plant. The sago cycad can be distinguished by a thick coat of fibers on its trunk. The sago cycad is sometimes mistakenly thought to be a palm, although the only similarity between the two is that they look similar and both produce seeds. Names Cycads are not related to palms (Arecaceae), superficially similar only in leaf arrangement and that both are vascular plants and seed plants. The Latin specific epithet ''revoluta'' means "curled back", in reference to the leaves. This is also called kungi (comb) palm in Urdu speaking areas. Description This very symmetrical plant supports a crown of shiny, dark green leaves on a thick shaggy trunk that is typically about in diameter, sometim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycas Circinalis
''Cycas circinalis'', also known as the queen sago, is a species of cycad known in the wild only from southern India. ''Cycas circinalis'' is the only gymnosperm species found among native Sri Lankan flora. Taxonomy ''C. circinallis'' is native to southern India and Sri Lanka, but the species name was formerly widely used for similar cycads in Southeast Asia, which leads to confusion in modern sources. The specimens described as "''C. circinallis''" in Indonesia and New Guinea are now recognized as '' Cycas rumphii''; while the taxon formerly described as the subspecies ''C. circinallis'' ssp. ''riuminiana'' from the Philippines is now regarded as a separate species, '' Cycas riuminiana''. Cultivation The plant is widely cultivated in Hawaii, both for its appearance in landscape and interiors, and for cut foliage. File:Cycas circinalis - sago palm - desc-top of trunk.jpg, Male cone, new File:Cycas circinalis 002.JPG, Male cone, old File:Cycas circinalis at Kadavoor.jpg, Youn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioon Edule
''Dioon'' is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. Description Dioons are dioecious, palmlike shrubs with cylindrical stems, usually with many leaves. The species in the genus ''Dioon'' are perennial, evergreen cycads with cylindrical stem axis is partially in the ground. The plant is thickened and made of soft wood, rarely having above ground branches. Leaf bases are persistent or shedding to leave smooth bark. The leaves are pinnate, spirally arranged, interspersed with cataphylls, with leaflets not articulated and lacking a midrib. The lower leaflets are often reduced to spines. The sporophylls are not in vertical rows in cones, and the megasporophyll apices are broadly flattened, upturned, and overlapping. Species in the genus Dioon have 2n = 18 chromosomes. The largest species is '' D. spinolosum'', which are over 16 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
