Diatoms of North AmericaDiatoms of North America
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Guide to Surirella cruciata

A.Schmidt 1877

Surirella Cruciata Guide
Credit: Jana Veselá
  1. Valve with cuneate footpole and broadly rounded headpole
  2. Central part of valve distinctly raised
  3. Central porcae distinct
  4. Axial area narrow, elevated in a keel

Valves are obovoid with cuneate footpole and broadly rounded headpole. Larger specimens are distinctly heteropolar. The valve face is distinctly and abruptly raised in the central third of the valve. Porcae are pronounced in the central part of valve, arranged in an opposite to alternate pattern. The axial area is narrow, lacks ornamentation and is elevated in a shallow keel. The alar canals are narrower than the fenestrae, usually even in density throughout.