Stephanodiscus Hantzschii Fo Tenuis Guide
Credit: David Burge
  1. Valve face flat
  2. Spines prominent
  3. Annulus present
  4. Valves lightly silicified
  5. Fascicles multiseriate

The valve face is flat. Valves are often lightly silicified. An annulus is present at the valve center. Central fultoportula are absent. Fascicles are multiseriate and may be wavy. Prominent spines terminate each interfascicle.