Phylum: Charophyta   Family: Closteriaceae

Closterium calosporum var. brasiliense  F. Børgesen 1890

First described and illustrated by Børgesen (1890: 29, pl. 2: 5). As the varietal name suggests, it has a cosmopolitan distribution. Longer and more common than the nominate variety.
Cell dimensions: L: 113-157 µm; B: 8.9-10.1 µm; Ap: 2.1-2.6 µm; Arc: 95-108°; L/B: 12.6-15.8.
Zygospore dimensions: 20 x 17.4 µm.
A common taxon, tolerant of a range of habitats from neutral to quite acidic.

References: 
Børgesen, F. (1890). Symbolae ad floram Brasiliae centralis cognoscendam.
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.
Van Westen, M. (2024). Sieralgen in Drenthe.
West, W. & West, G.S. (1904). A Monograph of the British Desmidiaceae, Volume 1.