| Drepanophycales | ||||||||
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Fossil
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Drepanophycales is an order of extinct plants of the Division Lycopodiophyta of ?Late Silurian to Late Devonian age, found in North America, China, Russia, Europe, and Australia. Sometimes known as the Asteroxylales or Baragwanathiales.
Description
Extinct terrestrial vascular plants of the Silurian to Devonian periods. Stem of the order of several mm to several cm in diameter and several cm to several metres long, erect or arched, dichotomizing occasionally, furnished with true roots at the base. Vascular bundle an exarch plectostele or actinostele, tracheids of primitive annular or helical type (so-called G-type). Stem clothed in either microphylls (leaves with a single vascular thread or 'vein'), or with leaf-like enations (unvascularized projections) with a vascular trace into the base of each enation. Homosporous, with sporangia borne singly and dehiscing by a single slit.
List of families
- Drepanophycaceae Kräusel & Weyland
- stem with microphylls
- Asteroxylaceae
- stem with unvascularized enations
References
- Pichi-Sermolli, R.E.G. (1958). The higher taxa of Pteridophyta and their classification. In: Systematics of today. (O. Hedberg, ed.). Uppsala Universitets Årsskrift 6:70-90.
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