''Taeniopteris'' is an extinct

form genus Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...

leaves, perhaps representing those of

cycads Cycads are seed plants that typically have a stout and woody ( ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or ...

, bennettitaleans, or marattialean

ferns A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

. The form genus is almost certainly a

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

category for unfertile leaves of a certain shape ("taeniopterids") which cannot be assigned to specific groups due to a lack of information on cuticle or

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

structures. The leaves are simple, with a strong central vein (

rhachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In th ...

) and an unbroken margin. The central vein leads to nearly perpendicular lateral veins, which may be slightly divided or undivided. The shape of the leaf is variable, but often elongated and smooth-edged. "Taeniopterid" leaves with bennettitalean-type cuticle are placed in the form genus ''

Nilssoniopteris ''Nilssoniopteris'' is an extinct form genus of leaves belonging to the Bennettitales. Leaves are slender and often entire-margined (smooth-edged), though some species have dissected leaves with numerous small segments extending down to the rachi ...

'', while those with cycad-type cuticle are placed within '' Nilssonia'' and related genera. Some fertile "taeniopterids" preserve spore packages, and can be assigned to marattialean ferns. ''Taeniopteris'' was named by Brongniart (1828) from an illustration of a

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations ...

leaf from Oxfordshire, as published by Sternberg (1823). This Oxfordshire specimen defined the type species, ''Taeniopteris vittata''. The largest and broadest "taeniopterid" leaves are named as the form genus ''Macrotaeniopteris'', which also represents cycad or bennettitalean leaves without preserved cuticle.

References

{{Taxonbar, from=Q17504831 Prehistoric plant genera Fossil taxa described in 1828