Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus subhexagonus  (West & G.S. West) Coesel 1993

First described by West & G.S.West (1912, p. 96, pl. 114: 6) under the cumbersome name of Arthrodesmus incus var. ralfsii f. subhexagona. Coesel (1993, p. 110) raised it to species rank. A rare desmid.

References: 
Coesel, P.F.M. (1993) Taxonomic notes on Dutch desmids II.
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.
West, W. & West, G.S. (1912) A Monograph of the British Desmidiaceae, Volume 4.