Phylum: Charophyta   Family: Desmidiaceae

Micrasterias papillifera J. Ralfs 1848

First described and illustrated by Ralfs (1848: 72, pl. 9: 1). West & West (1905: 91, pl. 44: 1,2,7) note: “This is the most abundant of the smaller British species of the genus …”
Cell dimensions: L: 100-150 µm; B: 100-140 µm; Is: 24-27 µm; L/B: 1.05-1.15.
This is nothing like as common as in the Wests’ days. An acidophile of moorland bogs. Rarely recorded.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Ralfs, J. (1848) The British Desmidieae.
West, W. & West, G.S. (1905) A Monograph of the British Desmidiaceae, Volume 2.