Lemnaceae

Leaves less than 1 cm wide Lemnaceae
Roots present on the undersurface
Roots variable in number on each cladode, often 2–5, only occasionally fewer or more
Cladodes elliptic to obovate, 3–10 mm long, with 7–16 veins; length/breadth ration 1–1.5 Spirodela
Cladodes ± round or broad-ovate, 2–5 mm long, with 3–7 veins; length/breadth ration 1.5–2 Landoltia