The Devonian land plant Protosalvinia

Abstract
Protosalvinia (= Foerstia) shows a number of morphological features suggesting it was a land plant, possibly an emergent aquatic. Certain kinds of biochemical data, as presently interpreted, also support the morphological evidence. The evidence supports neither a fucoid nor even an algal attribution for this enigmatic plant. Protosalvinia should be treated as the representative of a separate group of land plants as previously advocated. ''Tracheid-like'' tubes with internal spiral thickenings are, on the basis of direct comparison, morphologically identical to those of nematophytalean origin. They may have functioned in a capacity similar to the tracheids of vascular plants. The Nematophytales are non-marine plants of uncertain taxonomic position.