Phylum: Charophyta   Family: Desmidiaceae

Cosmarium rostafinskii R. Gutwinski 1890

First described by Gutwinski (1890: 67 [emended 1892: 41, pl. 1: 15]). Later, West, W. & West, G.S. (1908: 251, pl. 89: 8-10) made it a variety of C. speciosum suggesting it differs so little that it is scarcely justifiable to regard it as specifically distinct. They give a lower range of sizes as well as taking into account Gutwinski’s measurements and illustrate a cell (l.c. pl. 89: 9) with these small dimensions. Kouwets (in manuscript) refers to this cell and has bracketed the lower sizes suggesting it might represent a different species. Interestingly, The Harris find reflects these lower measurements. A rare desmid found in atmophytic habitats such as ephemeral pools and with moss on wet rocks.

References: 
Gutwinski, R. (1890) Zur Wahrung der Priorität.
Gutwinski, R. (1892) Flora glonów okolic Lwowa. (Flora algarum agri Leopoliensis).
West, W. & West, G.S. (1908) A Monograph of the British Desmidiaceae, Volume 3.
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.