Glossary terms starting with "d"


A crossing pattern of rows of areolae. The rows, or striae, may cross in three directions: a transapical row and two opposing oblique rows. The striae of the genera Decussata and Pleurosigma have this pattern.

Distal raphe

The portion of a raphe branch that is near the valve end, or valve apex. See also proximal raphe.


The side of the valve that is wider and more convex than the ventral side. Occurs in genera that are asymmetrical to the apical axis, such as Cymbella and Encyonema. From Latin for back of the body.