Glossary terms starting with "d"


Areolae may be spaced such that they form striae, or rows, in three directions. Decussate areolae form a transapical striae and two opposing oblique rows of striae. Such patterns are found in the genera Decussata and Pleurosigma.

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.