Equisetopsida
Equisetum telmateia
The Equisetopsida (referred to in paleobotanical literature Sphenopsida ) are a class of vascular plants. The Equisetopsida However tart represented originated in Devon, their greatest diversity in the coal forests of the Carboniferous and are limited only by the horsetails.
- 3.1 Literature
- 3.2 Notes and references
Features
Members of the Equisetopsida characterized by nodes in structured with intermediate internodes stems. The trunks of some fossil groups, such as the Calamites the coal forests were lignified, reaching stature heights of up to 30 meters and 1 meter diameter trunk, while other groups were more herbaceous and remained significantly smaller. The stems are usually hollow inside. The internodes are m. o w. distinctly ribbed, reflecting the progression of vascular bundles. The strains originate from a rhizome, which forms adventitious roots at the nodes. The leaves are always arranged in whorls. The horsetails are the leaves subulate ( Mikrophylle ), while the wedge -leaved plants usually wedge-like leaves had widened with branching veins. The spores are formed in sporangia, which are in sporangia and are usually arranged in cone-like strobili as. The sporangia are either specially trained sprouts ( sporophylls ) and separately from the photosynthetically active Trophophyllen (eg horsetails ) or as " Blossom" at the end of the Trophophylle (eg Bowmanites type). The Sporangienstände were in some fossil species either heterosporous or isospor ( as well as the extant horsetails ).
System
Outer systematics
The Equisetopsida are part of the ferns in the narrower sense ( Monilophyten ) and sister group to the Marattia -like ferns ( Marattiopsida ).
Seed plants ( Spermatophyta )
Pteridopsida ( Polypodiopsida )
Marattiopsida
Equisetopsida
Bärlapppflanzen ( Lycopodiopsida )
The Marattiopsida (at least the recent ) are isospor as the recent Equisetopsida, but the spores ( Sporotrophophyllen ) are formed there in green, partly branched fronds. The Polypodiopsida both Isospory and heterospory are known and the spores are usually, but not always formed at Sporotrophophyllen. This diversity of spore types and the position of the sporangia is also evident in fossil Equisetopsida.
Inside systematics
The internal system is not uniform in the literature, as most groups are present only fossil. Taylor et al. 2009 distinguish three subgroups:
- Pseudoborneales (Devon)
- Wedge -leaved plants [ Sphenophyllales ] ( Devonian to Triassic)
- Equisetales (Devon tart up ) Calamitaceae
- Tchernoviaceae
- Gondwanastachyaceae
- Equisetaceae
Pseudoborneales
The Pseudoborneales are monotypic (only Pseudobornia ursina ). Pseudobornia made from up to 30 m high structured, woody, hollow stems. In the first branching order only 1 to 2 branches per node, in the second branching order decussate ( dekussiert ) were formed and eventually arranged pseudozweizeilig. The leaves are formed only in the final branches and are arranged in whorls of four. Each leaf consists of a doubly forked split petiole and leaf blades corresponding to four heavily slashed. The fertile sections to sit at the end of primary branches and form of sporangium. The sporangia are heterosporous. The systematic position of the Pseudoborneales is unclear, however, because of their age they can be considered as representative of the primal Equisetopsida.
Wedge -leaved plants
The wedge -leaved plants can indeed be detected already in the late Devonian, but they are very often only in the understory of forests in the Carboniferous coal and can be up to Triassic prove. There are herbaceous plants whose growth is interpreted as crawling up klimmend. The shoots branch dichotomously and carry through the vascular bundles triarchen 6-9 (-18 ) leaves per whorl. The leaves have dichotomously branching leaf veins and usually wedge- like shape ( hence the name ). The sporangia are loosely arranged in strobili or cone-like and always isospor.
Equisetales
Like the wedge -leaved plants occur in the first representatives of Equisetales that Calamites in the late Devonian, but are dominant and there like a tree only in the Carboniferous. However, the Calamites disappear already in the Permian, while Tchernoviaceae and Gondwanastachyaceae can be found to the Cretaceous and Equisetaceae to exist today. The Calamitaceae are like a tree growing plants with hollow branched stems. The leaves are arranged in whorls lanceolate to acicular. The sporangia are isospor or heterosporous and are cone-like in sporangia on bracts ( bracts ). Tchernoviaceae and Gondwanastachyaceae form isospore sporangia in strobili not from, but into fertile internodes, in which the sporangia are in table-shaped sporangia. The Equisetaceae the leaves are sheath-like and subulate with a maximum of one per leaf vein Papers ( Mikrophyll ). They form peg-like strobili without bracts, in which sporangia are in table-shaped sporangia. Fossil Equisetaceae are often classified as Equisetites, during the recent all belong to the genus Equisetum.