11. Pediastrum duplex Meyen

(Fig. 3I, J)

Discoid colony, hyaline, clathrate,with a flattened star-like shape. Size variable, with ca. 16 smooth-walled to microverrucate cells. Bifurcated cells at the periphery of the colony, with characteristic elongated processes. Internal cells with distinct morphology. Colony diameter ca. 40–123 µm (x 68 µm). As in P.boryanum, colony usually found with irregular folds in sediment due to its fragile structure. Ecological data: as described for P. boryanum .