Annual or perennial. Vegetative stem elongate, floating or on mudflats; flowering stem to 20 cm long, the lower internode usually repent. Sessile leaves not seen; petiolate leaves floating or emersed, oval to round, obtuse to acute at apex, cuneate to truncate at base, 2.5-4.5 cm long, 3-6 cm wide; petiole glabrous, to 20 cm long. Stipules 5-10 cm long. Inflorescence with up to 20 flowers; peduncle pilose, 3-5 cm long; spathe 2.5-4 cm long. Flowers pilose, tube 4-8 mm long, tepals blue or white, 10-14 mm long; upper stamens 2-10 mm long, lower stamens 7-14 mm long, the anthers ovoid to oblong, 0.6-1.2 mm long, larger on the longer stamens; ovary 2-3 mm long; tristylous. Nutlet about 14 mm long, including apical attenuate spine.
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