Phylum: Charophyta   Family: Desmidiaceae

Cosmarium moniliforme var. limneticum W. West & G.S. West 1908

First described and illustrated by West & West (1908: 23, pl. 67: 6-7). It differs only slightly in size from the nominate variety, mainly in its broader isthmus. The Wests also note: “It is readily distinguished by the slight angularity of the apices and the wide isthmus.” However, other authors have pointed out that this angularity also occurs when cell-division has just taken place.
Cell dimensions: L: 33-54 µm; B: 17-28 µm; Is: 11-15; L/B: 1.70-1.90.
In the Outer Hebrides it has be found in silty loch-margins, and boggy moorland pools in slightly acidic to slightly alkaline habitats. It is infrequently recorded.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.
West, W. & West, G.S. (1908) A Monograph of the British Desmidiaceae, Volume 3.