Tryblionella Guide
Credit: Marina Potapova, Pat Kociolek
  1. Raphe eccentric
  2. Valve face with longitudinal undulation

Valves are typically linear-lanceolate to elliptic in some species. Like Nitzschia, Tryblionella possesses an eccentric raphe, positioned in a canal along one valve margin. The raphe systems within a frustule are positioned on opposite, in the manner of nitzschioid symmetry. The raphe canal is supported by fibulae. Valves have a distinct longitudinal undulation on the face.

Although Tryblionella was described in 1853, many recent floras treat members of Tryblionella within Nitzschia. Species within Tryblionella occur in both freshwater and marine habitats.