Girdle view brightfield	valve view brightfield
Girdle view brightfield mantle focus	Girdle view brightfield near mid-focus

Description
Cells are rectangular in girdle view and are usually seen in this aspect rather than in valve view. The valve face is circular and flat. The mantle and girdle have barely any structure visible in LM.

Character	State
If circular, diameter	(8)-13-30-(35) µm
If circular, mantle depth	4-14-(17) µm
Spines	Absent
If circular, central area relative to marginal zone	Not differentiated
If circular, striae on valve face	Restricted to margin
If circular, central ornamentation	Unmarked, structureless
If circular, extent of valve face areolae	Restricted to valve face
Rimoportulae	Present
	Absent
Fultoportulae, marginal	Absent
Fultoportulae, valve face	Absent

Habit

Character	State
Colonies	Cells linked cell-to-cell
If linked cell-to-cell	Chain with valve faces abutting
Attachment	Not attached (floating or freely motile)

True	Rarely True	Unknown
Only by Misinterpretation

Synonyms

• Gallionella varians Ehrenberg 1836

Ecological Information
Common in freshwater habitats, especially eutrophic waters. In rivers, it often forms fine brown filaments in marginal areas where the current is not so strong but these filaments are easily scoured away during spates.