Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus subtriangularis  (O. Borge) E. Teiling 1948

First described and illustrated by Borge (1897: 212, pl. 3: 4) as Arthrodesmus incus var. subtriangularis. Later moved to Staurodesmus by (Teiling 1948: 64). Cells usually 3-radiate. Semicell body a little longer than broad with a V-shaped sinus. The lower lateral sides indented; upper part slightly convex. Apex elevated with a median dent. Spines parallel to slightly divergent.
Cell dimensions with spines: L: 25-40 µm; B: 45-75 µm; Is: 6.5-9.5 µm.
An infrequently recorded acidophile, found in moorland bogs and abandoned peat-cuttings.

References: 
Borge, O. (1897) Algologiska Notiser. 3-4. Zur Kenntnis der Verbreitungsweise der Algen. 3 Süsswasser-Plankton aus der Insel Mull.
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Teiling, E. (1948) Staurodesmus, genus novum. Containing monospinous Desmids.