Craticula

An internal valve occurring in species in the genus Craticula. This craticular valve consists of a raphe-sternum and robust transverse bars. Frustules with normal morphology produce the craticular valve under conditions of high solute concentration. The formation of these internal valves is not linked to mitosis.

Craticula 1  L 9 62
Image Credit: Sarah Spaulding
High level of focus showing parallel striae of the normal valve.
Craticula 2  L 9 62
Image Credit: Sarah Spaulding
Mid level of focus showing the robust transverse bars of the internal craticula stage.
Craticula 3  L 9 62
Image Credit: Sarah Spaulding
Deep level of focus showing both the craticula and the radiate striae of the heribaudii stage.