Phylum: Charophyta   Family: Desmidiaceae

Euastrum inerme (J. Ralfs) P.M. Lundell 1871

First described by Ralfs (1848: 89, pl. 16: 7e) and illustrated by Jenner as Euastrum elegans var. inerme. It was later raised to species rank by Lundell (1871: 20). Above the isthmus is a noticeable protuberance, above that are two smaller protuberances. In the centre of the semicell is a large scrobicula.
Cell dimensions: L: 45-60 µm; B: 30-40 µm; Is: 8-13 µm; Th: 20-25; L/B: 1.45-1.70.
An acidophile of boggy habitats and shallow vegetated lochs. A Europe-wide rare species but, interestingly, West & West (1905: 25) say "… but often occurs in great abundance in the west of Scotland, the Outer Hebrides, and the west of Ireland." Recent studies suggest this is no longer the case; however, when found it can be locally common.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Lundell, P.M. (1871). De Desmidiaceis, quae in Suecia inventae sunt, observationes criticae.
Ralfs, J. (1848). The British Desmidieae.
Ruzicka, J. (1977). Die Desmidiaceen Mitteleuropas, Volume 1, Part 2.
West, W. & West, G.S. (1905). A Monograph of the British Desmidiaceae, Volume 2.