Progymnosperm
| Progymnosperm Temporal range: Middle Devonian–Mississippian | |
|---|---|
 | |
| Archaeopteris fossil leaves | |
Scientific classification  | |
| Kingdom: | Plantae |
| Division: | Tracheophyta |
| Class: | †Progymnospermopsida |
| Orders | |
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The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the gymnosperms.[1] They have been treated formally at the rank of division Progymnospermophyta or class Progymnospermopsida (as opposite). The stratigraphically oldest known examples belong to the Middle Devonian order the Aneurophytales, with forms such as Protopteridium, in which the vegetative organs consisted of relatively loose clusters of axes.[2] Tetraxylopteris is another example of a genus lacking leaves. In more advanced aneurophytaleans such as Aneurophyton these vegetative organs started to look rather more like fronds,[3] and eventually during Late Devonian times the aneurophytaleans are presumed to have given rise to the pteridosperm order, the Lyginopteridales. In Late Devonian times, another group of progymnosperms gave rise to the first really large trees known as Archaeopteris.
Other characteristics:
- Vascular cambium with unlimited growth potential is present as well as xylem and phloem.
- Ancestors of the earliest seed plants as well as the first true trees.
- Strong monopodial growth is exhibited.
- Some were heterosporous but others were homosporous.
Phylogeny
Progymnosperms are a paraphyletic grade of plants.[4][5]
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Progymnosperm |
Taxonomy
An updated classification of Progynopserms based on the work by Novíkov & Barabaš-Krasni 2015[6] with plant taxon authors from Anderson, Anderson & Cleal 2007[7]
- Genus †Pertica Kasper & Andrews 1972
- Order †Cecropsidales Stubblefield 1969
- Family †Cecropsidaceae Stubblefield 1969
- Order †Protopityales Nemejc 1963
- Family †Protopityaceae Solms-Laubach 1893
- Class †Noeggerathiopsida Krysht. 1934
- Order †Noeggerathiales Darrah 1939
- Family †Noeggerathiaceae Göpp. ex von Eichwald 1854
- Order †Discinitales Doweld 2001
- Family †Discinitaceae Gao & Thomas 1994
- Order †Tingiales Zimmermann 1959
- Family †Tingiaceae Koidzumi 1938 [Tingiostachyaceae Gao 1987]
- Order †Noeggerathiales Darrah 1939
- Class †Aneurophytopsida Bierhorst ex Takhtajan 1978 [Protopteridiopsida]
- Order †Aneurophytales Kräusel [Protopteridiales Hoeg 1942]
- Family †Aneurophytaceae Kräusel & Weyland 1941 [Protopteridiaceae (Kräusel 1932) Kräusel & Weyland 1941]
- Family †Protokalonaceae Barnard & Long 1975
- Order †Aneurophytales Kräusel [Protopteridiales Hoeg 1942]
- Class †Archaeopteridopsida Takhtajan 1978
- Order †Archaeopteridales Zimmermann 1930 [Siderallales Nemejc 1963; Svalbardiales Nemejc 1963]
- Family †Archaeopteridaceae Schmalhausen 1894 [Siderallaceae Nemejc 1961; Svalbardiaceae (Zimmermann 1950) Novak 1961]
- Order †Archaeopteridales Zimmermann 1930 [Siderallales Nemejc 1963; Svalbardiales Nemejc 1963]
References
- ↑ Stewart, W.N.; Rothwell, G.W. (1993). Paleobiology and the evolution of plants. Cambridge University Press. p. 521pp.
- ↑ Lang, W. H. (1925). "Contributions to the study of the Old Red Sandstone flora of Scotland. I. On plant-remains from the fish-beds of Cromarty. II. On a sporangium-bearing branch-system from the Stromness Beds." Transactions of the Royal Society of Edinburgh, 54: 253-279.
- ↑ Serlin, B. S. & Banks, H. P. (1978). "Morphology and anatomy of Aneurophyton, a progymnosperm from the Late Devonian of New York. Palaeontographica Americana, 8: 343-359.
- ↑ Crane, P.R.; Herendeen, P. & Friis, E.M. (2004), "Fossils and plant phylogeny", American Journal of Botany, 91: 1683–99, doi:10.3732/ajb.91.10.1683, PMID 21652317
- ↑ Pelletier (2012). "Empire biota: taxonomy and evolution 2nd ed". Lulu.com: 354. ISBN 1329874005.
- ↑ Novíkov & Barabaš-Krasni (2015). "Modern plant systematics". Liga-Pres: 685. doi:10.13140/RG.2.1.4745.6164. ISBN 978-966-397-276-3.
- ↑ Anderson, Anderson & Cleal (2007). "Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology". Strelitzia. SANBI. 20: 280. ISBN 978-1-919976-39-6.