Plants caespitose or with spreading rhizomes. Rhizomes generally well developed. Culms simple. Leaf sheaths tightly convolute, persistent, upper margins finely lacerated. Maleinflorescence with many paniculate florets not arranged in spikelets; spathes soon caducous. Male spikelets: bracts and perianth segments chartaceous, equal, white; anthers exserted at anthesis. Femaleinflorescence with large spathes partially obscuring clusters of female spikelets at fertile nodes. Femalespikelets: bracts chartaceous, all except topmost one sterile; perianth segments small, hyaline, equal; staminodes 0; ovary 1-locular; styles 2, plumose, +/- as long as ovary. Fruit a large, woody nutlet, without elaiosome.
Plants caespitose, rarely mat-forming. Rhizomes short or long. Culms simple or branching. Leaf sheaths closely convolute. Maleinflorescence of many small spherical to elliptical spikelets; spathes caducous. Malespikelets: bracts small, taller than florets, cartilaginous; anthers exserted at anthesis. Femaleinflorescence of (1-)several spikelets; spathes similar to sheaths, persistent. Femalespikelets: bracts bony, tightly convolute into spindle-shaped spikelets, with 2 or 3 bracts fertile; perianth segments 6, subequal, hyaline, small to minute; ovary 1-locular; styles 2, free to base, plumose, slightly longer to much longer than ovary. Fruit a shiny, adaxially flattened, black nutlet with an elaiosome.
Species +/- 7, mainly Western Cape, to Albany District in Eastern Cape.
Plants caespitose or tangled. Rhizomes very short. Culms branching, sometimes sparsely. Leaf sheaths persistent, either closely convolute or somewhat spreading. Maleinflorescence similar to female ones, paniculate with (1-)many discrete, compact spikelets; spathes relatively insignificant. Malespikelets: florets many; perianth compressed; perianth segments 6, outer lateral ones usually boat-shaped, villous to glabrous on midrib; anthers exserted at anthesis. Femaleinflorescence similar to male, but spikelets often somewhat larger. Femalespikelets: bracts cartilaginous or osseous, usually somewhat longer than florets, usually uppermost 1-many fertile; perianth segments cartilaginous or bony, outer lateral perianth segments keeled, rarely winged or villous; staminodes well developed; ovary 1-locular, styles usually 3, plumose, exserted from behind bracts at anthesis. Fruit a soft-walled nutlet.
Species +/- 24, mainly Western Cape, also Northern Cape (Namaqualand) and Eastern Cape to KwaZulu-Natal.
Plants tightly caespitose. Rhizomes usually very short. Culms simple. Leafsheaths caducous. Maleinflorescence very similar to female. Malespikelets: florets sometimes smaller than female ones; pollen released inside perianth segments. Female inflorescence of many elongated, poorly defined spikelets clustered at several fertile nodes; spathellae and bracts taller than florets, hyaline and soon lacerate, persisting as hairs around maturing florets; spathes taller or smaller than spikelets, papery to cartilaginous. Female spikelets: perianth segments osseous, usually acute, backs all rounded, inner segments usually longer than outer ones; staminodes well developed; ovary 3-locular; styles 3, plumose. Fruit at least partly dehiscent.
Plants generally tangled, forming cushions, rarely monoecious, or florets bisexual. Rhizomes 0. Culms branching, sometimes flattened or striate. Leaf sheaths closely convolute, apex often with a long, hair-like mucro. Maleinflorescence of several spicate spikelets. Malespikelets with several bracts fertile; anthers exserted at anthesis. Femaleinflorescence similar to male, but with fewer spikelets, of 1-several spicate spikelets; spathes similar to sheaths. Femalespikelets similar to male ones, bracts chartaceous to cartilaginous, with 1 fertile; perianth segments membranous, subequal; ovary 1-locular; styles 2. Fruit a soft-walled nutlet.
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.
Annual or perennial aquatic herbs, erect, usually deciduous, rhizomatous. Leaves radical, emergent, petiolate, with cordate to ovate blade, extremely variable as to size and shape. Flowers pedicelled, racemose or subumbellate. Perianth segments free, subequal, blue, marcescent. Stamens 3 + 3, arising from base of segments, unequal, the largest with an erect tooth on one side of filament; anthers erect, basifxed, opening by apical slits. Ovary 3-locular, with axile placentas, many-ovulate; style filiform; stigma apical, small. Capsule spindle-shaped, with thin pericarp enclosed by marcescent perianth. Seeds many, minute, ovoid, with several thin ribs. x= 10, 13, 14 (aneuploids, high polyploidy).
Species 8, tropical Africa, Asia and Australia, naturalised in Europe; 1 in sthn Afr.: Monochoria africana (Solms) N.E.Br., only known from central and southern parts of the Kruger National Park and from a neighbouring private game reserve (Mpumalanga); apparently annual, growing in or around the edge of pans.
Perennial aquatic herbs, rhizomatous, rooting in mud. Leaves with long swollen spongy petiole with expanded sheathing bases; blade cordate, hastate, or ovate, or sometimes all leaves submerged and linear. Flowers small, in terminal spike, rarely 2 or solitary, occasionally some cleistogamous. Perianth nearly regular, salver- or funnel-shape, blue, accrescent. Stamens 3 (1 in cleistogamous flowers), exserted; filaments arising from throat of tube; median stamen occasionally longer; anthers dorsifixed, opening by longitudinal slits. Ovary 1-locular or imperfectly 3-locular, with 3 parietal, multi-ovulate placentas; style filiform; stigma small. Capsule oblong or terete. Seeds many, ovoid, terete.
Species +/- 9, tropical to subtropical regions of Africa and America; 1 in sthn Afr.: Heteranthera callifolia Rchb. ex Kunth (= H. kotschyana Fenzl ex Solms), Namibia, Botswana and from the Nylsvlei area in the Northern Province.