Pteridospermatophyta

Pteridosperms, also known as seed ferns, are a polyphyletic grouping of extinct seed-producing plants. The earliest fossil evidence for plants of this type are the lyginopterids of late Devonian age. They flourished particularly during the Carboniferous and Permian periods. Pteridosperms declined during the Mesozoic Era and had mostly disappeared by the end of the Cretaceous Period, though Komlopteris seem to have survived into Eocene times, based on fossil finds in Tasmania.

Glossopteris (etymology: from Ancient Greek γλῶσσα, glôssa 'tongue' + πτερίς, pterís 'fern') is the largest and best-known genus of the extinct Permian order of seed plants known as Glossopteridales (also known as Arberiales, Ottokariales, or Dictyopteridiales). The name Glossopteris refers only to leaves, within the framework of form genera used in paleobotany, used for leaves of plants belonging to the glossopterid family Dictyopteridiaceae.

Glossopteridales is an extinct order of seed plants, known from the Permian of Gondwana. They arose at the beginning of the Permian, and the majority or all members of the group became extinct during the Permian–Triassic extinction event, 251.9 mya. Possible Triassic records of the group have been recorded. The best known genus is Glossopteris, a leaf form genus. Other examples are Gangamopteris, Glossotheca, and Vertebraria.

The Caytoniales are an extinct order of seed plants known from fossils spanning from the Middle Triassic (Anisian) to the Late Cretaceous (Campanian). They are regarded as "seed ferns" because they are seed-bearing plants with fern-like leaves. Although at one time considered angiosperms because of their berry-like cupules, that hypothesis was later disproven. Nevertheless, many authorities consider them likely ancestors or close relatives of angiosperms. The origin of angiosperms remains unclear, and they cannot be linked with any known seed plants groups with certainty.

The Medullosales is an extinct order of pteridospermous seed plants characterised by large ovules with circular cross-section and a vascularised nucellus, complex pollen-organs, stems and rachides with a dissected stele, and frond-like leaves. Their nearest still-living relatives are the cycads.

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; they are the stratigraphically oldest-known pteridosperms, occurring first in late Devonian strata; and they have the most primitive features, most notably in the structure of their ovules. During early and most of middle Pennsylvanian times the Medullosales took over as the more important of the larger pter

Dicroidium is an extinct genus of fork-leaved seed plants. 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 (). Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar, the Indian subcontinent and Antarctica.

Callistophytales is an extinct order of spermatophytes (seed plants) which lived from the Pennsylvanian (Late Carboniferous) to Permian periods. They were mainly scrambling and lianescent (vine-like) plants found in the wetland "coal swamps" of Euramerica and Cathaysia. Like many other early spermatophytes, they could be described as "seed ferns", combining ovule-based reproduction with pinnate leaves superficially similar to modern ferns.

Sphenopteris is a genus of seed ferns containing the foliage of various extinct plants, ranging from the Devonian to Late Cretaceous. One species, S. höninghausi, was transferred to the genus Crossotheca in 1911.

REDIRECT Calamopityaceae

Alethopteris is a prehistoric plant genus of fossil pteridospermatophytes (seed ferns) that developed in the Pennsylvanian (around ). thumb|left|Alethopteris florentina De Stefani, 1901, Natural History Museum University of Pisa thumb|Alethopteris, at the State Museum of Pennsylvania in Harrisburg.|left thumb|Alethopteris sp.

Gangamopteris is a genus of Carboniferous-Permian plants, very similar to Glossopteris. Previously, it was classified as fern with reproduction by seed. The genus is usually only applied to leaves, making it a form taxon. Gangamopteris dominates some coal deposits, such as those of the Beacon Supergroup.

Gigantopterids (Gigantopteridales) is an extinct, possibly polyphyletic group of seed plants known from the Permian period. Gigantopterids were among the most advanced land plants of the Paleozoic Era and disappeared around the Permian–Triassic extinction event around 252 million years ago. Though some lineages of these plants managed to persist initially, they either disappeared entirely or adapted radically, evolving into undetermined descendants, as surviving life prospered again in much-altered ecosystems. One hypothesis proposes that at least some "gigantopterids" became the ancestors of