Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus mucronatus (C. Nägeli) K. Thomasson 1955

First described by Nägeli (1849: 125) as Phycastrum mucronatum. It was later moved to its current genus by Thomasson (1955: 200). The semicells in this nominate variety are elliptical with very small, laterally inserted, spines.
Cell dimensions: L: 20-26 µm; B: 20-25 µm; Is: 5-7.5 µm; Sp: 1-3.5 µm; Overall B: 24-31.
West, West & Carter (1923: 12), as Staurastum mucronatus, record its distribution in Scotland as general but scarce. Found in mesotrophic waters.

References: 
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.
Nägeli, C. (1849). Gattungen einzelliger Algen, physiologisch und systematisch bearbeitet.
Thomasson, K. (1955). Studies on South American fresh-water plankton. 3. Plankton from Tierra del Fuego and Valdivia.
West, W., West, G.S. & Carter, N. (1923). A Monograph of the British Desmidiaceae, Volume 5.