Sycidiales is an order of fossil

charophyte Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a phylum, division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly fro ...

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

. The reproductive structures in Sycidales (and Trochiliscaceae, placed in

Trochiliscales Trochiliscaceae is a family of fossil charophyte green algae. It is the only member of the order Trochiliscales. The reproductive structures in Trochiliscaceae (and families placed in Sycidiales by AlgaeBase) have a calcified cover, called a ''utr ...

AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both marine and freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael Guiry. Text was copied from this source, which is avai ...

) have a calcified cover, called a ''utricle'', that is thought to prevent the

zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellula ...

being desiccated. Other

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

families lack this cover, as do modern charophytes. Fossils of the family Sycidiaceae are found over the longest time span, from the

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

to the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

Families and genera

, AlgaeBase accepted the following families and genera. *† Chovanellaceae **†'' Chovanella'' Reitlinger & Yartseva – 1 species *† Sycidiaceae Karpinsky **†'' Calcisphaera'' Williamson – 4 species **†'' Gemmichara'' Zhen Wang – 1 species **†'' Maslovella'' Samojlova – 1 species **†''

Sycidium ''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending i ...

'' G.Sandberger – 12 species

References

Charophyta Green algae orders {{Green alga-stub