Sycidiales is an order of fossil

charophyte Charophyta () is a paraphyletic group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision. The terrestrial plants, the Embryophyta emerged deep within Charophyta, possibly from terres ...

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

. The reproductive structures in Sycidales (and

Trochiliscaceae 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 ''ut ...

, placed in Trochiliscales by

AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both seaweed, marine and freshwater algae, freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael D. Guiry, Michael Guiry. Text ...

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

zygote A zygote (; , ) is a eukaryote, eukaryotic cell (biology), 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 individ ...

being desiccated. Other

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

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 23.5 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 third and shortest period of t ...

to the

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

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 in ...

'' G.Sandberger – 12 species

References

Charophyta Charophyta orders {{Green alga-stub