Phylum: Charophyta   Family: Desmidiaceae

Micrasterias americana J. Ralfs 1848

West & West (1905: 117) note: “… is principally characterized by the form of its lateral lobes. It has a wide distribution in the British Islands but is an uncommon species.” Interestingly, the greater number of records are from Scotland but none for either the Inner or Outer Hebrides.
Cell dimensions (2): L: 139-140 µm; B: 124-144 µm; Is: 29-30 µm; L/B: 0.97-1.13.
A rarely recorded acidophile, found in moorland bogs and abandoned peat-cuttings.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Van Westen, M.C. (2024). Sieralgen in Drenthe.
West, W. & West, G.S. (1905). A Monograph of the British Desmidiaceae, Volume 2.