Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus triangularis var. brevispina (V. & P. Allorge) P.F.M. Coesel & K.J. Meesters 2013

First described and illustrated by Allorge & Allorge (1930: 37, fig. 10: 42-44) as Arthrodesmus triangularis var. brevispina. It was more recently moved to its current genus by Coesel & Meesters (2013: 37, pl. 7: 7-13). It differs in having the spines less than two-thirds the breadth of the cell body. The isthmus is usually angular at its apex but can also be rounded. The spines are usually parallel but occasionally slightly decumbent.
Cell dimensions: L: 20-22 µm; B: 16-21 µm; Is: 5-7.1 µm; Th: 8-9 µm; Sp: 5-9 µm; Overall B: 31-38.
An acidophile found in moorland pools and bogs including with Sphagnum. Infrequently recorded.

References: 
Allorge, V. & Allorge, P. (1931). Hétérocontes, Euchlorophycées et Conjuguées de Galice. Matériaux pour la flore des algues d'eau douce de la Péninsule Ibérique I.
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.