''Sirogonium'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of filamentous
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 ...
of the
order
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
...
Zygnematales
The Zygnematales ( (''zygós'') and νῆμα (''nḗma'') ( nom.), νήματος (''nḗmatos'') ( gen.)), also called the Conjugatales, are an order of green algae, comprising several thousand different species in two families. The larger fam ...
. It is found in
freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...
areas on all continents but Antarctica. ''Spirogyra'' measures approximately 32–115
μm
The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...
in width. Each cell contains 2–10 chloroplasts in a ribbon, in contrast to the closely related genus ''
Spirogyra
''Spirogyra'' (common names include water silk, mermaid's tresses, and blanket weed) is a genus of filamentous charophyte green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is charact ...
'', which has chloroplasts in a coil.
Molecular phylogenetic
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
studies have placed ''Sirogonium'' inside a clade consisting of ''Spirogyra'' species; in other words, ''Spirogyra'' is
paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
with respect to ''Sirogonium''.
Species
The following species are currently accepted:
* ''
Sirogonium calosporum''
Zhu
* ''
Sirogonium ceylanicum''
Wittrock
* ''
Sirogonium decoratum''
Prescott
* ''
Sirogonium denticulatum''
W.J.Zhu
* ''
Sirogonium floridanum''
(Transeau) G.M.Smith
* ''
Sirogonium fuscosporum''
Woodhead & Tweed
* ''
Sirogonium guangzhouense''
Zhu
* ''
Sirogonium hui''
(L.C.Li) Transeau
* ''
Sirogonium illinoisense''
(Transeau) G.M.Smith
* ''
Sirogonium indicum''
Singh
* ''
Sirogonium inflatum''
Dixit
* ''
Sirogonium kamatii''
Kadlubowska
* ''
Sirogonium khoriense''
Masud-ul-Hassan & M.Nizamuddin
* ''
Sirogonium melanosporum''
(Randhawa) Transeau
* ''
Sirogonium phacosporum''
Skuja
* ''
Sirogonium pseudofloridanum''
(Prescott) Transeau
* ''
Sirogonium reticulatum''
Randhawa
* ''
Sirogonium retroversum''
H.C.Wood
* ''
Sirogonium sticticum''
(Smith) Kützing
* ''
Sirogonium vandalurense''
Iyengar
* ''
Sirogonium ventersicum''
Transeau
References
* John Whitton, B.A. and Brook, A.J. (editors) 2002. ''The Freshwater Algal Flora of the British Isles.'' Cambridge University Press, Cambridge. .
{{Taxonbar, from=Q22286377
Zygnemataceae