scapigerous, aquatic herbs, rootstocks tuberous or stoloniferous, covered with
numerous root fibres. Leaves floating or submerged, oblong, membranous.
Inflorescence of spikes, flowers bisexual on long scapes, young spike enclosed
in conical sheath, deciduous. Perianth pink, white or pale blue, 1-3, segments
equal or unequal or obsolete. Stamens 6 or more, filaments subulate,
unequal, persistent, anthers didynamous.
Carpels 3-6, each with 2 or more ovules. Fruit of 3 or more follicles. Seeds
erect, testa thick or thin, embryo straight.