Phylum: Charophyta   Family: Desmidiaceae

Staurodesmus incus var. indentatus (West & G.S.West) Coesel 2007

West & West (1912, p. 94, pl. 113: 20-24) as Arthrodesmus incus var. indentatus, named this variety for the distinct indentations in the lateral sides of the semicells. They describe it as on of the most frequent British varieties, but today it is rarely encountered in the Outer Hebrides.

References: 
West, W. & West, G.S. (1912) A Monograph of the British Desmidiaceae, Volume 4.
Coesel, P.F.M. (2007). Taxonomic notes on Dutch desmids IV: new species, new names, new combinations.