Frustulia Rexii Guide
Credit: Carrie Graeff
  1. Valves strongly rhomboid
  2. Poroids present at external central area
  3. Abruptly widened longitudinal ribs near apices
  4. Striae circumradiate apices
  5. Valve slightly constricted at apices

The valves of F. rexii are strongly rhomboid, with a very slightly constriction at the valve apices. A group of external poroids is present in the central area. Near the apices the longitudinal ribs are abruptly wider, giving the longitudinal ribs a unique appearance. Striae circumradiate the apices.