Butomaceae Mirb.
Perennial aquatic, sometimes lactiferous, herbs. Leaves basal or cauline, sheathing at base. Flowers conspicuous, bisexual, actinomorphic, solitary or in involucrate umbels; sepals 3, usually subherbaceous, persistent; petals 3, larger, usually thin, deciduous. Stamens hypogynous, mostly 6-9, occasionally fewer, if numerous then arranged in many whorls and outer often staminodia; filaments flattened, free; anthers basifixed, 2-celled, opening by lateral slits. Carpels 6 or more, free or united at base; ovules numerous. Follicles free or nearly so, dehiscing adaxially. Seeds many. Genera 5, of temperate and tropical regions.
