Wolffia cylindracea Hegelm.

Shoot flattened-drum shaped, rounded at the front, very strongly domed, and with numerous small stomata, [shoot] twice as long as broad. Cell tissue of the dorsal side of the shoot with smaller cells that that of the ventral side. Adult individuals are 0.54-0.72 mm long, from one side margin to the other 0.26-0.41mm wide; ratio of both diameters is about 4:9 in the longest [individuals]. The stomata are only 0.018-0.019mm long. Welwitsch (Mspt.) describes the colour as vibrant dark green.