Aquatic, usually rooted in soil, sometimes free-floating; stems elongate, with long, pendent roots at lower nodes. Petioles to 30 cm long, not markedly inflated; blades round to obovate, rounded or mucronate at apex, truncate to obtuse at base, to 15 cm long, lacking midvein. Spikes many-flowered, axillary, with a subensheathing spathe at base; flowers 6-parted; perianth +/- funnelform, 3.5-5.5 cm long, purplish-blue with a yellow spot on the upper, expanded perianth lobe, the tube 2-3 cm long, glandular-pubescent, the lobes erose-margined, decurrent; stamens 6, unequal, the 3 shorter ones included; filaments adnate to tube, glandular-pubescent; style ca 2 cm long, glabrous; stigma red, capitate. Capsules with seeds 1-1.6 mm long, less than 1 mm wide. Shattuck 409.