Algae World: Sellaphora

Diversity: the 'seminulum group'

Sellaphora: seminulum group

Description

In the 'seminulum group', the valves are small, from linear, lanceolate or elliptical. There are no polar bars. The axial area is narrow, and the central area is rectangular or rounded. The axial area is not depressed and there is no conopeum. In LM there are no grey areas or lines parallel to the raphe..

The small size of the valves (lengths generally < 20 µm) separates these species from most other Sellaphora species. In addition, the absence of polar bars separates them from the 'bacillum group' and the 'pupula group', and the narrow axial area separates them from the 'americana group'. There is no reason to think that this is a natural group.

Species list

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