Phylum: Charophyta   Family: Desmidiaceae

Staurastrum oxyacanthum W. Archer 1860

First described and illustrated by Archer (1860: 462, pl. [7: 1-2) as Staurastrum oxyacantha. [The paper was read before the Dublin Natural History Society, 1859].
Cell dimensions: L: 30-40 µm; B: 42-55 µm; Is: 10-12 µm.
Found in marginal vegetation of lochs and moorland pools, also bogs. Quite a rare species in Britain with most records coming from the west-coast regions.

References: 
Archer, W. ([1859], 1860). Description of two new species of Staurastrum.
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.
West, W., West, G.S. & Carter, N. (1923). A Monograph of the British Desmidiaceae, Volume 5.