Wolffia Horkel ex Schleid.
Roots absent Wolffia
Cladodes green, shining on the upper surface, up to 1 mm long, ± convex, rounded on the edges, with 50–80 stomata on the upper surface. Widespread. Still water, usually in grazing land Wolffia australiana
Cladodes whitish green in the centre of the upper surface, green towards the edges, up to 0.8 mm long, flat near the apex, acute on the edges, with up to 25 stomata on the upper surface. Coast and Cumberland Plain Wolffia angusta