Compare Rhoicosphenia abbreviata
Compare
Rhoicosphenia abbreviata can be distinguished from various species of the genus Gomphonema by the strong arch of the valve (as seen in girdle view), the reduced raphe on the dorsal valve, and the presence of more developed pseudoseptae. A number of species within Rhoicosphenia are thought to be present within North America, including R. californica and R. stoermeri. Rhoicosphenia californica has narrow valves with protracted apices. Rhoicosphenia stoermeri has a distinct central area, panduriform in shape.
LM scalebar = 10 µm
Length Range
10–55 µm
10–55 µm
Width Range
4–8 µm
4–8 µm
Striae in 10 µm
15-20
15-20
Rhoicosphenia californica
Length Range
8-50 µm
8-50 µm
Width Range
3-6 µm
3-6 µm
Striae in 10 µm
11-12 in the center valve, 13-15 at the ends
11-12 in the center valve, 13-15 at the ends
Rhoicosphenia stoermeri
Length Range
25-84 µm
25-84 µm
Width Range
6-9 µm
6-9 µm
Striae in 10 µm
11-13 in the center valve, 14-16 at the ends
11-13 in the center valve, 14-16 at the ends