Haslea Guide
Credit: Loren Bahls
  1. Valves lanceolate with acute apices
  2. Central costae thickened, forming a narrow fascia
  3. Raphe sternum with asymmetric thickened area in the central valve
  4. Striae crossed by longitudinal strips

Valves are lanceolate with acute apices and a central raphe system. Two or three thickened transapical costae on either side of the valve center form a narrow fascia. The raphe sternum is thickened on one side of the axial area and is fused to the central ribs, giving valves a cruciform appearance. Striae are uniseriate, containing rectangular or square poroids, and overlain externally by fine longitudinal strips, many of which may be continuous from pole to pole.

Haslea is primarily an epipelic and planktonic genus of marine habitats, but contains at least one species found in brackish inland waters: Haslea spicula (Hickie) Lange-Bert.