Guide to Gomphonema
Credit: Sarah Spaulding
- Valve outline club-shaped
- Single stigma present, or absent
- Apical pore field present
- Striae uniseriate
Valves are symmetric to the apical axis, and asymmetric to the transapical axis. In valve view, valves are club-shaped, or clavate. In girdle view, frustules are wedge-shaped, or cuneate. A stigma may be present on one side of the central area. An apical pore field is present and bisected by the terminal raphe. Striae are uniseriate. Striae are not crossed by longitudinal lines, as in Gomphoneis.
Many species grow on mucilaginous stalks and can be found in nearly every habitat type within circumneutral lakes and streams of North America.