Prehistoric plant genera

Calamites is a genus of extinct arborescent (tree-like) horsetails to which the modern horsetails (genus Equisetum) are closely related. Unlike their herbaceous modern cousins, these plants were medium-sized trees, growing to heights of . They were components of the understories of coal swamps of the Carboniferous Period (around ).

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.

Cooksonia is an extinct group of primitive land plants, treated as a genus, although probably not monophyletic. The earliest Cooksonia date from the middle of the Silurian (the Wenlock epoch); the group continued to be an important component of the flora until the end of the Early Devonian, a total time span of . While Cooksonia fossils are distributed globally, most type specimens come from Britain, where they were first discovered in 1937. Cooksonia includes the oldest known plant to have a stem with vascular tissue and is thus a transitional form between the primitive non-vascular bryophyte

Rhynia is a single-species genus of Devonian vascular plants. Rhynia gwynne-vaughanii was the sporophyte 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.

Archaeopteris is an extinct genus of progymnosperm tree with fern-like leaves. A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous (), the oldest fossils being 385 million years old, and had global distribution.

Aglaophyton major (or more correctly Aglaophyton majus) was the sporophyte generation of a diplohaplontic, pre-vascular, axial, free-sporing land plant of the Lower Devonian (Pragian stage, around ). It had anatomical features intermediate between those of the bryophytes and vascular plants or tracheophytes.

Horneophyton is an extinct early plant which may form a "missing link" between the hornworts and the Rhyniopsida. It is a member of the class Horneophytopsida. Horneophyton is among the most abundant fossil organisms found in the Rhynie chert, a Devonian Lagerstätte in Aberdeenshire, UK. A single species, Horneophyton lignieri, is known. Its probable female gametophyte is the form taxon Langiophyton mackiei.

thumb|Wattieza casasii

Pecopteris is a very common form genus of leaves. Most Pecopteris leaves and fronds are associated with the marattialean tree fern Psaronius. However, Pecopteris-type foliage also is borne on several filicalean ferns, and at least one seed fern. Pecopteris first appeared in the Devonian period, but flourished in the Carboniferous, especially the Pennsylvanian. Plants bearing these leaves became extinct in the Permian period, due to swamps disappearing and temperatures on Earth dropping.

Annularia is a form taxon, applied to fossil foliage belonging to extinct plants of the genus Calamites in the order Equisetales.

genus of plants (fossil)

thumb|Fossil of Psilophyton dawsonii

Psaronius is an extinct genus marattialean tree fern which grew to 10m in height, and is associated with leaves of the organ genus Pecopteris and other extinct tree ferns. Originally, Psaronius was a name for the petrified stems, but today the genus is used for the entire tree fern. Psaronius tree fern fossils are found from the Carboniferous through the Permian. thumb|left|Reconstruction of Psaronius, Illustrated by Auguste Faguet (1877)

Tortilicaulis is a moss-like plant known from fossils recovered from southern Britain, spanning the Silurian-Devonian boundary (around ). Originally recovered from the Downtonian of the Welsh borderlands, Tortilicaulis has since been recovered in the famous Ludlow Lane locality.

Equisetites is an extinct genus of vascular plants within Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. The genus was named by Sternberg (1833) and contains at least 40 named species and two unnamed species, with the earliest known species being E. hemingwayi from the Westphalian of Yorkshire, England, though the affinity of this genus to modern Equistaceae is uncertain.

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.

Pseudobornia is a genus of plants known only from fossils found from the Upper Devonian. It contains a single species Pseudobornia ursina, and is the earliest fossil assigned with certainty to the Equisetopsida.

Pertica is a genus of extinct vascular plants of the Early to Middle Devonian (around ). It has been placed in the "trimerophytes", a strongly paraphyletic group of early members of the lineage leading to modern ferns and seed plants.

Calamophyton is an extinct genus of tree, or "tree-sized plant", that was extant in the Middle Devonian period. As of 2024, a well-preserved fossilized forest of Calamophyton trees discovered in Somerset, England, represents the earliest-known forest.

thumb|Palaeozoic fructifications of Ferns or Pteridosperms|alt= thumb|'''Psaronius|Psaronius sp. - trunk section|alt= thumb|Pecopteris arborescens - compression foliage'''

Protosphagnum nervatum is the only known species of order Protosphagnales. It is only known from the Permian fossil record. In many ways, it resembles the living moss genus Sphagnum, though its leaf cells are not as strongly dimorphic as in Sphagnum.

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.

Chiropteris is an extinct genus of plants that existed from the Early Permian (Sakmarian stage) to the Late Jurassic (?Oxfordian stage, maybe latter).

Neocalamites is an extinct genus of equisetalean plant. Neocalamites thrived during the Permian and Triassic, and occurs worldwide.

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.

Umaltolepis is an extinct genus of seed plant, known from the Early Jurassic to Early Cretaceous of Asia. Within the form classification system used within paleobotany, it refers to the seed-bearing reproductive structures, which grew on woody plants with strap-shaped Ginkgo-like leaves assigned to the genus Pseudotorellia.