Phylum: Charophyta   Family: Desmidiaceae

Micrasterias jenneri J. Ralfs 1848

A characteristic species with the sinus linear and closed. Polar and lateral lobes with closed incisions, sub-divided lobes with minor incisions which are slightly open and retuse. Polar lobe very broad and retuse.
Cell dimensions: L: 155-173 µm; B: 109-121 µm; Is: 28-35 µm; L/B: 1.35-1.48.
West & West (1905: 87) record it as very uncommon, occurring principally in upland areas, with Sphagnum in particular. This reflects the current situation in the Outer Hebrides.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
West, W. & West, G.S. (1905). A Monograph of the British Desmidiaceae, Volume 2.