Perennial, aquatic, scapigerous
herbs, glabrous, with tuberous rhizomes. Leaves long, elliptic-lanceolate, ovate
or ovate-cordate, petiole thick, scape short, radical, sheathing at base.
Inflorescence of an umbel, supported by an involucre of bracts. Perianth 6,
imbricate, outer 3 herbaceous, persistent, inner 3 bright yellow and deciduous.
Stamens up to 29, included in sepals. Fruit of follicles, whorled or slightly
connate, hemispherical, membranous, laterally flattened, dehiscent in dorsal
suture. Seeds oblong, subquadrate, numerous.