Perennial emergent herb; stem erect, 1-leaved, with several sheathing, bract-like leaves at base. Leaves obtuse, margins entire with parallel, outwardly curved-convergent venation; blades lanceolate, ovate, cordate, sagittate, hastate or reniform; foliage dark green to greyish. Petiole of leaf of floral shoot short; petioles of other leaves long; bases sheathing and clasping, sheaths ligulate. Inflorescence a spike with few to many blue, white or white-green flowers, enclosed by a spathe and petiole base of leaf of floral shoot. Flowers irregular, bilabiate, largest perianth lobe with a bilobed yellow spot. Stamens unequal, in two groups of 3 each, adnate to perigone tube; anthers introrse, dorsifixed, versatile, dehiscing longitudinally; filaments and perigone tube covered with hairs terminating in pinhead-like glands. Ovary with 2 carpels aborted and 1 fertile, 1-locular, 1-ovulate; ovule pendulous, anatropous; placentation parietal. Fruit a 1-seeded, indehiscent nut, enclosed by a hardened perigone base, toothed, smooth or with spinulose ridges; pericarp rich in glutin. Seeds reniform or ovoid; endosperm white, copious, surrounding a cylindrical embryo. x= 8 (polyploidy).
Species 4, tropical to warm America, naturalised in Australia, Europe and sthn Afr.: * Pontederia cordata L. var. ovalis Solms, originally from tropical South America, is sold in local nurseries as an ornamental water plant and has become naturalised locally and may become invasive.