Phylum: Charophyta   Family: Desmidiaceae

Staurastrum brevispina var. boldtii G. Lagerheim 1893

First described by Lagerheim (1893: 163). Borge (1894: 36, pl. 3: 42) described and illustrated a variety: S. brevispina var. retusum. This was later regarded as a synonym of boldtii. The relevance is that boldtii is predominant retuse. It is also longer than broad.
Cell dimensions: L: 84-41 µm; B: 32-35 µm; Is: 9.6-12.6 µm; L/B: 1.19-1.23.
Prefers slightly acidic habitats and found in the plankton of shallow, vegetated lochs. A rare taxon.

References: 
Borge, O. (1894) Süsswasser-Chlorophyceen gesammelt von Dr, A. Osw. Kihlman im nördlichsten Russland, Gouverment Archangel.
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Lagerheim, G. (1893) Chlorophyceen aus Abessinien und Kordofan.
West, W., West, G.S. & Carter, N. (1923) A Monograph of the British Desmidiaceae, Volume 5.