Image © Marien van Westen
Cell dimensions (L x B): ca 25 x 20 µm
Euastrum binale, in particular its var. gutwinskii, is one of the most common desmid species in acidic, oligotrophic moorland pools and bogs. Despite the small dimensions and a lack of conspicuous cell wall ornamentation it may be readily recognized. Semicells are trapezoid-pyramidal in outline with a slightly dilated apex marked by acute angles and a wide, shallow, V-shaped median incision. Var. gutwinskii differs from the nominate variety by having an additional lateral lobe in between the basal and the apical lobe. Zygospores are only incidentally encountered.
Image © Henk Schulp
Dichotypical cell of Eu. binale. The upper semicell is characteristic of the nominate variety, the lower one rather of var. gutwinskii.
Image © Marien van WestenZygospore of Eu. binale (var. gutwinskii).
SEM picture of Eu. binale var. gutwinskii showing scrobiculation of the cell wall in a zone around the slightly inflated centre of the semicell (mouse over).