Stephanodiscus Alpinus Guide
Credit: Loren Bahls
  1. Valves small
  2. Fascicles uniseriate to biseriate at margin
  3. Areolae relatively coarse
  4. Marginal spine on every interfascicle
  5. Areolae in central area disorganized

Valves are less than 33 ┬Ám in diameter with a marginal spine on every interfascicle. Areolae are relatively coarse and arranged in fascicles that are uniseriate near the valve center to biseriate near the valve margin. Areolae in the central area are disorganized.