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The Caytoniales (Figs. 1-2) are an extinct order of seed plants known from fossils collected throughout the Mesozoic Era, around 2] [3] [4] They are regarded as seed ferns because they are seed-bearing plants with fern-like leaves. [4]
It is the archetypal genus of the corystosperms, an extinct group of seed plants, often called "seed ferns", assigned to the order Corystospermales or Umkomasiales. Species of Dicroidium, which grew as large trees, were widely distributed and dominant over Gondwana during the Triassic ( 252 to 201 million years ago ).
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 ]
Fossilized fronds of the Carboniferous-Early Cretaceous seed fern Alethopteris †Alethopteris †Alethopteris davreuxi †Alethopteris decurrens †Alethopteris grandini †Alethopteris serlii †Alethopteris valida †Amphiscapha † Ananias †Annularia †Annularia sphenophylloides †Annularia stellata †Anomphalus †Anthracoceras
The Lyginopteridales are an extinct group of seed plants known from the Paleozoic.They were the first plant fossils to be described as pteridosperms (a polyphyletic group sometimes referred to as "seed ferns") and, thus, the group on which the concept of pteridosperms was first developed; [2] they are the stratigraphically oldest-known pteridosperms, occurring first in late Devonian strata; [3 ...
Historically both lycophytes and monilophytes were grouped together as pteridophytes (ferns and fern allies) on the basis of being spore-bearing ("seed-free"). In Smith's molecular phylogenetic study the ferns are characterised by lateral root origin in the endodermis , usually mesarch protoxylem in shoots, a pseudoendospore, plasmodial tapetum ...
The morphology of peltasperm leaves is highly variable, ranging from dissected pinnate (fern-like) to forked and simple morphologies. The leaves of many peltasperms have "monocyclic stomata with wedge-shaped subsidiaries ending in a beak-like papilla overarching the guard cells", something which is found among other seed plant groups. The seed ...
The Dicroidium plant (which bore Dicroidium leaves, Umkomasia seed bearing structures and Pteruchus pollen organs) is thought to have grown as large trees, with trunks at least 10 metres (33 ft) tall and over 50 centimetres (20 in) wide. [7] Some other possible corystosperms like Pachypteris may have grown as shrubs. [8]