Spaulding, S.,
Edlund, M.
(2008).
Orthoseira.
In Diatoms of North America.
Retrieved May 01, 2026, from https://diatoms.org/genera/orthoseira?x-craft-preview=409442409a997390693ff24c7010fd6f1c96fb56f8f091fa016a63de9a54aaccecpiqubknd
Centric
Orthoseira
Carinoportulae one to several, near midvalve
Spines marginal, variable in length
Frustules linked by spines to form short chains
The frustules of Orthoseira are cylindrical and form filamentous colonies linked by marginal spines. The valve surface is flat and possesses one or more unique process, the carinoportula. Internally, the valves may (or may not) have internal 'caverns', positioned at the valve mantle interface. The marginal spines, if present, are...