Phylum: Charophyta   Family: Gonatozygacea

Gonatozygon aculeatum W.N. Hastings 1892

First described and illustrated by Hastings (1892: 29, text fig.) from Nashua, New Hampshire & Osceola, Missouri, north-eastern & eastern U.S. Apices slightly swollen with two small granules visible in face-view. Spines are usually about 3 µm but can be up to 10, especially at the apices.
Cell dimensions: L: 100-300 µm; B: 6-15 µm; L/B: 10-30.
A rare species largely confined to the Atlantic north-west in Europe. Found in acidic moorland pools, lochans and disused peat-cuttings.

References: 
Brook, A.J. & Williamson, D.B. (2010) A Monograph on some British Desmids.
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Hastings, W.N. (1892) A proposed new desmid.
Ruzicka, J. (1977) Die Desmidiaceen Mitteleuropas, Volume 1, Part 1.