Frustules biraphid, rhomboidal to linear-lanceolate, with straight to undulate margins. Raphe contained in a median rib extending most of the length of the valve, proximal and distal raphe ends not clearly observed with light microscopy in northern Michigan specimens. At the apices the raphe rib has the appearance of a pencil or crayon tip. Striae fine, arranged so as to produce a pattern of apical and transapical rows. Cells single or occasionally occurring in mucilaginous tubes.
Light Microscope Image(s)
Each image is accompanied by the genus and species, California Academy of Sciences slide number (ie. CAS 612010), location of the specimen on the slide, and dimension in microns.