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Polysporangiophytes
Polysporangiophytes, also called polysporangiates or formally Polysporangiophyta, are plants in which the spore-bearing generation (sporophyte) has branching stems (axes) that bear sporangia. The name literally means 'many sporangia plant'. The clade includes all land plants (embryophytes) except for the bryophytes (liverworts, mosses and hornworts) whose sporophytes are normally unbranched, even if a few exceptional cases occur. While the definition is independent of the presence of vascular tissue, all living polysporangiophytes also have vascular tissue, i.e., are vascular plants or tracheophytes. Extinct polysporangiophytes are known that have no vascular tissue and so are not tracheophytes. Early polysporangiophytes History of discovery Paleobotanists distinguish between micro- and megafossils. Microfossils are primarily spores, either single or in groups. Megafossils are preserved parts of plants large enough to show structure, such as stem cross-sections or branching patte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horneophytopsida
The Horneophytopsida, informally called horneophytes, are a class of extinct plants which consisted of branched stems without leaves, true roots or vascular tissue, found from the Late Silurian to the Early Devonian (around ). They are the simplest known polysporangiophytes, i.e. plants with sporophytes bearing many spore-forming organs (sporangia) on branched stems. They were formerly classified among the rhyniophytes, but it was later found that some of the original members of the group had simple vascular tissue and others did not. The group has also been treated as the division Horneophyta. In 2004, Crane et al. published a cladogram for the polysporangiophytes in which the Horneophytopsida are shown as the sister group of all other polysporangiophytes. One other former rhyniophyte, ''Aglaophyton'', is also placed outside the tracheophyte clade, as it did not possess true vascular tissue (in particular did not have tracheids), although its conducting tissue is more complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladoxylopsid
The cladoxylopsids are an extinct group of plants related to ferns and sphenopsids. They had a central trunk, from the top of which several lateral branches were attached. Fossils of these plants originate in the Middle Devonian to Early Carboniferous periods (around ), mostly just as stems. Cladoxylopsida contains two orders. The order Hyeniales is now included in Pseudosporochnales. Intact fossils of the Middle Devonian cladoxylopsid '' Wattieza'' show it to have been a tree, the earliest identified in the fossil record as of 2007. In 2019, experts from Cardiff University, UK; Binghamton University and the New York State Museum discovered more fossils of Cladoxylopsida and Archaeopteris in a quarry in Cairo, New York. A recent (2017) discovery in Xinjiang in China of early Late Devonian ( Frasnian, ca. 374 Ma) silicified fossil cladoxylopsid tree trunks (diameter up to c.70 cm) with preserved cellular anatomy showed an internal arrangement with many xylem bundles in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aglaophyton
''Aglaophyton major'' (or more correctly ''Aglaophyton majus'') was the sporophyte generation of a diplohaplontic, pre-vascular, axial, free-sporing land plant of the Lower Devonian (Pragian stage, around ). It had plant anatomy, anatomical features intermediate between those of the bryophytes and vascular plants or tracheophytes. ''A. major'' was first described by Kidston and Lang in 1920 as the new species ''Rhynia major''. The species is known only from the Rhynie chert in Aberdeenshire, Scotland, where it grew in the vicinity of a silica-rich hot spring, together with a number of associated vascular plants such as a smaller species ''Rhynia gwynne-vaughanii'' which may be interpreted as a representative of the ancestors of modern vascular plants and ''Asteroxylon, Asteroxylon mackei'', which was an ancestor of modern clubmosses (Lycopsida). Description The stems of ''Aglaophyton'' were round in cross-section, smooth, unornamented, and up to about 6mm in diameter. Kidston an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyniophyte
The rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus ''Rhynia'', found in the Early Devonian (around ). Sources vary in the name and Taxonomic rank#Ranks in botany, rank used for this group, some treating it as the class Rhyniopsida, others as the subdivision Rhyniophytina or the division Rhyniophyta. The first definition of the group, under the name Rhyniophytina, was by Harlan Parker Banks, Banks, since when there have been many redefinitions, including by Banks himself. "As a result, the Rhyniophytina have slowly dissolved into a heterogeneous collection of plants ... the group contains only one species on which all authors agree: the type species ''Rhynia gwynne-vaughanii''". When defined very broadly, the group consists of plants with dichotomously branched, naked aerial axes ("stems") with terminal spore-bearing structures (sporangia). The rhyniophytes are considered to be stem group tracheophytes (vascular plants). Def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uskiella
''Uskiella'' is a genus of small fossil plants of Early Devonian age (around ). The diagnostic characters are naked axes branching isotomously, terminating in ellipsoidal, vertically elongate flat sporangia which split longitudinally into two valves. Spores of ''U. reticulata'' have a reticulate appearance. Coalified specimens have been reported from Wales, with a possible occurrence in Australia. The relationships of the genus are not clear because many anatomical details remain unknown. In 2004, Crane et al. published a cladogram for the polysporangiophytes in which ''Uskiella'' is basal to the lycophytes (clubmosses and relatives). Hao and Xue in 2013 listed the genus as a rhyniophyte The rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus ''Rhynia'', found in the Early Devonian (around ). Sources vary in the name and Taxonomic rank#Ranks in botany, rank used for this group, .... References Early Devonian plants P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pertica
''Pertica'' is a genus of extinct vascular plants of the Early to Middle Devonian (around ). It has been placed in the " trimerophytes", a strongly paraphyletic group of early members of the lineage leading to modern ferns and seed plants. Description ''Pertica quadrifaria'' (the type species of the genus) was described in 1972 from compression fossils found in the Trout Valley Formation of northern Maine, USA. It was an upright plant which grew to perhaps as much as a metre (3 ft) in height. It comprised a main, straight stem (axis) with side branches which developed dichotomously, branching many times at increasingly shorter intervals. Some of the terminal branchlets bore masses of erect paired, ellipsoidal sporangia in distinctive tight clusters. The branches were arranged in a spiral pattern, forming four vertical rows. The specific epithet ''quadrifaria'' refers to this growth habit. ''Pertica varia'' was described in 1976 from the Devonian of Eastern Canada. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fern
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaf, leaves called megaphylls that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled Fiddlehead fern, fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae (plant), Polypodiidae) and eusporangiate ferns, the latter group including horsetails, Psilotaceae, whisk ferns, marattioid ferns, and ophioglossoid ferns. The fern crown group, consisting of the leptosporangiates and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equisetopsida
Equisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-like branches radiating at regular intervals from a single vertical stem. The Equisetidae were formerly regarded as a separate division of spore plants and called Equisetophyta, Arthrophyta, Calamophyta or Sphenophyta. When treated as a class, the names Equisetopsida s.s. and Sphenopsida have also been used. They are now recognized as rather close relatives of the ferns (Polypodiopsida) of which they form a specialized lineage. However, the division between the horsetails and the other ferns is so ancient that many botanists, especially paleobotanists, still regard this group as fundamentally separate at the higher level. Description The horsetails comprise photosynthesising, "segmented", hollow stems, sometimes filled with pith. At the ju ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moniliformopses
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate ( Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. The fern crown group, consisting of the leptosporangiates and eusporangiates, is estimated to have originated in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
