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Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. [ citation needed ] Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs.
"A classification for extant ferns" (PDF). Taxon. 55 (3): 705–731. doi:10.2307/25065646. JSTOR 25065646. Archived from the original (PDF) on 2021-12-09 First attempt to provide a comprehensive classification for all ferns based on molecular data.
Pteridophytes (ferns and lycophytes) are free-sporing vascular plants that have a life cycle with alternating, free-living gametophyte and sporophyte phases that are independent at maturity. The body of the sporophyte is well differentiated into roots, stem and leaves. The root system is always adventitious. The stem is either underground or ...
Rhynia gwynne-vaughanii was the sporophyte [2] generation of a vascular, axial, free-sporing diplohaplontic embryophytic land plant of the Early Devonian that had anatomical features more advanced than those of the bryophytes. Rhynia gwynne-vaughanii was a member of a sister group to all other eutracheophytes, including modern vascular plants.
Tmesipteris, the hanging fork ferns, is a genus of ferns, one of two genera in the family Psilotaceae, order Psilotales (the other being Psilotum). Tmesipteris is restricted to certain lands in the Southern Pacific, notably Australia, New Zealand and New Caledonia.
The vascular bundles trifurcate at the nodes, with the central branch becoming the vein of a microphyll, and the other two moving left and right to merge with the new branches of their neighbours. [5] The vascular system itself resembles that of the vascular plants' eustele, which evolved independently and convergently. [5]
The Pteridophyte Phylogeny Group classification of 2016 (PPG I) recognized 13 genera. [5] Shortly afterwards, the genus Gastoniella was created for three species formerly placed in Anogramma which a molecular phylogenetic analysis had shown to be distinct.
Pteridospermatophyta, also called "pteridosperms" or "seed ferns" are a polyphyletic [1] grouping of extinct seed-producing plants.The earliest fossil evidence for plants of this type are the lyginopterids of late Devonian age. [2]