Cell body longitudinally assymmetrical (one side more domed than another), 13-16 μm long, 6-10 μm wide,
papilla present, with a flattened apex;
chloroplast parietal, asymmetrically located at one side; a pyrenoid at central-lateral;
stigma rounded, located anterior to the pyrenoid (near equator); nucleus at posterior half of the cell body.
[var. gallica Bourrelly 1951]: Cell body ovoid, 14-22 μm long, 7-16 μm wide; both corners of papilla slightly extruded becoming dichotomous; stigma elliptical; sexual reproduction anisogamy.
[var. minima Bourrelly 1961]: Anterior more sharpened; papilla conical; "Ausmaße" ? small (8 x 4 μm).
[var. triangularis Ettl 1965]: Cell body triangular in shape, 8-11 μm long, 6-10 μm wide; pyrenoid large. (Süßwasserflora von Mitteleuropa 9, Chlorophyta I, 1983).