Sirogonium is a genus of filamentous charophyte green algae of the order Spirogyrales. It is found in freshwater areas on all continents but Antarctica. Spirogyra measures approximately 32–115 μm in width. Each cell contains 2–10 chloroplasts in a ribbon, in contrast to the closely related genus Spirogyra, which has chloroplasts in a coil. Molecular phylogenetic studies have placed Sirogonium inside a clade consisting of Spirogyra species; in other words, Spirogyra is paraphyletic 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. .