Boottia Wallich; Oligolobos Gagnepain.

Herbs, freshwater. Stems usually cormlike. Leaves all basal, petiolate, usually sheathing at base; blades submerged or sometimes floating, linear to broadly ovate, 3-11-veined. Spathes elliptic or ovate, usually 2-6-winged, apex bifid or trifid, with 1 to many flowers. Flowers bisexual or unisexual and plants dioecious. Male flowers with longer pedicel. Bisexual and female flowers shortly pedicellate or without pedicel. Sepals 3, greenish, linear, oblong, or ovate. Petals 3, colored, orbicular to broadly obovate, much longer and wider than sepals. Stamens 3-15; filaments linear, flattened; anthers laterally dehiscent; staminodes (absent or 1-)3, often present in female flowers. Ovary of 3, 6, or 9 (or more) carpels; ovules numerous; stigmas 2 per style, linear. Fruit cylindric, fusiform, or conic. Seeds numerous, small, often hairy.

About 21 species: tropical to temperate areas; five species (two endemic) in China.