Genus Rhogostoma Belar, 1921

Belar (1921) described two Rhogostoma species that differed from freshwater Lecythium in four respects:

1. having a narrow crack-like, not a large round, aperture;
2. being filose not reticulose;
3. being several times smaller (R. minus 10-12 µm, R. schuessleri 15 µm);
4. thecae having bilateral not radial symmetry.