Wolffia arrhiza (L.) Horkel ex Wimm.
SUMMARY
Fronds spherical to ellipsoid, with the greatest width just below the surface of the water, 0.5-1.5 mm long, 0.4-1.2 mm wide, 1-1 1/3 times as long as wide, 1 1/4-1 1/2 times as deep as wide, with 10-100 stomata, bright green on the surface (not transparent). INFLORESCENCE: Plants occasionally flowering and rarely fruiting. INFRUCTESCENCE: Seeds 0.4-0.5 mm long, about 0.4 mm thick.