Diatoms of North AmericaDiatoms of North America
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Guide to Fragilaria socia

(Wallace) Lange-Bert. 1980

Fragilaria Socia Guide
Credit: Gina LaLiberte, Melissa Vaccarino
  1. Fascia present
  2. Central area expanded to both sides
  3. Valves taper toward the apices

Valves range from narrow and linear at the large end of the size range to fusiform. The central area is thickened, forming a fascia. The central area is expanded at the valve margins, except in smaller specimens where the central area is asymmetric. The ends are tapered toward the apices.