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Guide to Geissleria decussis

(Østrup) Lange-Bert. and Metzeltin 1996

G Decussis Guide
Credit: Marina Potapova
  1. Valves elliptical-lanceolate with rostrate to capitate apices
  2. Striae radiate, usually bent
  3. Central area comprised of short and long alternating striae
  4. Annulae in two rows at poles
  5. Stigma may be present in central area

Valves are elliptical-lanceolate with rostrate to capitate apices. Striae are radiate and often deflected, or bent. Short and long striae alternate in the central part of the valve. The presence of a stigma in the central area is a variable feature in the species.