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Name derivation:




Sphaerozyga C.Agardh, 1886;  of 7 species descriptions, at least one (S. flos-aquae) is considered to be a synonym of Aphanizomenon flos-aquae (Guiry and Guiry 2013).

Order Nostocales;  Family Nostocaceae



Trichomes, often tapering at both ends similar to Aphanizomenon species, are embedded in amorphous mucilage, include intercalary heterocysts either solitary or in pairs, with akinetes on each side (Cooke 1890).

Similar genera:


Calothrix tapers toward one end, not both, of filaments.



Roadside ditches, sometimes epiphytic on submerged Myriophyllum leaves.


Cooke, M.C.  1890.  Introduction to Fresh-Water Algae with an enumeration of all the British species.  The International Scientific Series, Vol. 69 (LXIX).  Kegan Paul, Trench, Trubner & Co., London.

Guiry, M.D. and G.M. Guiry  2013.  AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.  http://www.algaebase.org; searched on 28 February 2013.