Phylum: Charophyta Family: Desmidiaceae
Staurastrum avicula J. Ralfs 1848
First described and illustrated by Ralfs (1848: 140, pl. 23: 11). West & West (1923: 40) note: “Its uniform granulation and the pair of minute spicules at each angle of the broadly ovate semicells distinguish it.” Later authors include cells with more pronounced spines. These are rather similar to S. subcruciatum but that species is smaller and broader than long; also, the spines project at a slightly lower angle. Coesel & Meesters (2023: 221) note: “… is a taxonomically complex species that needs a serious revision.” Zygospore globose with long straight projections with a broadened base and furcate apices.
Cell dimensions: L: 22-45 µm; B: 27-48 µm; Is: 8-11 µm.
Zygospore diameter: minus projections: c.29 µm; overall: c.51 µm
A common acidophile, found in moorland bogs and abandoned peat-cuttings.
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. & Carter, N. (1923) A Monograph of the British Desmidiaceae, Volume 5.