Phylum: Charophyta   Family: Desmidiaceae

Pleurotaenium trabecula var. crassum V.B. Wittrock 1872

First described and illustrated by Wittrock (1872: 62, pl. 4: 17). This variety is broader and stockier than the nominate giving a smaller L/B ratio.
Cell dimensions: L: 240-450 µm; B: 30-48 µm; L/B: 6.5-10.5.
Much scarcer than the nominate variety. Found in circumneutral waters.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Wittrock, V.B. (1872). Om Gotlands och Ölands sötvattens-alger.