Czekanowskiales, also known as Leptostrobales, are an extinct group of

seed plants A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They inc ...

. Members of the family are distinguished by persistent leaves borne on deciduous short shoots, subtended by scale-like leaves. The leaves are highly dissected (divided into partitions). They likely grew as trees and shrubs. The main reproductive structure of Czekanowskiales, '' Leptostrobus,'' consists of bivalved seed-bearing round capsule-like structures arranged along a long axis. The fossil record of Czekanowskiales is largely confined to the Northern Hemisphere, and they inhabited warm-temperate and temperate climates under humid conditions. The oldest possible records of the group are ovulate cones from the Late

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

of Italy, but the group is primarily known from the Late

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

onwards, and were abundant during the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

and Early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

. Only a handful of species are known from the Late Cretaceous, confined to the northern

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admin ...

, corresponding to the decline of other seed plant groups during the explosive radiation of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s. The affinites of Czekanowskiales to other seed plants are obscure. A close relationship to the Ginkgoales have been proposed, based on similar preserved molecular signatures of fossil cuticles.

References

{{Taxonbar, from=Q15921856 Prehistoric plant orders Mesozoic plants Prehistoric gymnosperms