Valves of Reimeria are symmetric to the transapical axis and asymmetric to the apical axis. The dorsal margin is slightly arcuate. The ventral margin is markedly expanded, or tumid, at the central area. Apical porefields are present at both poles on the ventral margin and bisected by the distal raphe fissure. The axial area is narrow. A single stigma is positioned on the dorsal side of the central area. Distal raphe fissures are deflected toward the ventral margin.
Reimeria contains a few species, two of which are broadly distributed across North America in benthic habitats. Older literature contains this group within the Cymbella sinuata complex.