Home
Rhizomes branched or unbranched, erect or repent; elongate stolons present or absent. Leaves mostly floating (vernal leaves submersed; blades sessile, broad). Leaf blade orbiculate to widely ovate or elliptic, basal lobes divergent to overlapping, margins entire to spinose-dentate, apex of lobe acute or acuminate to widely rounded; primary venation mostly palmate, midrib with 1 vein. Flowers floating or emersed, opening diurnally or nocturnally; perianth perigynous, spreading at anthesis; sepals 4, mostly greenish, ovate to elliptic; petals 8-many, spirally arranged or wholly or partially whorled, showy, white, pink, blue, or yellow, broadly lanceolate or ovate to obovate, grading into stamens; stamens yellow or cream-colored, inserted on lateral surface of ovary, spreading at anthesis, sometimes with distal connective appendage; ovary shorter than petals and stamens; stigmatic disk with prominent, distinct, upwardly incurved appendages around margin. Fruits borne on curved or coiled peduncles. Seeds nearly globose to ellipsoid, to 5 mm; aril present. x = 14.
Delicate to robust aquatic herbs with usually stout often tuberous rhizomes. Leaves small to large, floating, emergent, or submerged, usually ± round or oval, often slightly to distinctly peltate, cordate, palmately nerved, entire to dentate; stipules present. Sepals 4 (but ± sepaloid petals can be present), ± green. Petals 5–numerous, inserted at successively higher levels on the ovary, the outermost usually equalling or shorter than the sepals, the innermost shorter and narrower and grading into the stamens. Stamens numerous, the outer with broad petaloid filaments, all inserted towards the top of the ovary; anthers obtuse or with connective produced as an appendage. Ovary syncarpous, many-locular with numerous ovules in each locule; stigmatic surfaces radiating from central apical boss of the ovary and with marginal stylar processes. Fruit fleshy or spongy, ripening under water and eventually splitting. Seeds small, floating due to air-containing sack-like pulpy aril and seed-wall.
Herbs perennial. Rhizomes erect, ascending, or repent, branched or unbranched. Leaves mostly floating; leaf blade venation primarily palmate, base cordate to sagittate, margin entire to dentate, sometimes slightly peltate. Flowers floating or emersed, perianth spreading. Sepals 4, greenish, not petaloid, inserted at base of ovary, sometimes persistent. Petals 8 to many, large and showy, inserted on surface of ovary, often grading into stamens. Stamens shorter than sepals and petals, inserted on lateral surface of ovary; filament linear to ovate or obovate; anther connective appendaged or unappendaged. Carpels partially or completely united. Style absent or modified into abaxially projecting carpellary appendages. Stigma sessile, radiate on cup-shaped stigmatic disc rimmed by carpellary appendages. Fruit irregularly dehiscent. Seeds globose, ovoid, or ellipsoid, smooth or longitudinal ridges pubescent, arillate.
Annual or perennial; rhizomes vertical or horizontal, cylindrical or tuberous; with or without stolons. Leaves spirally arranged, floating when mature; petiole entire or winged; lamina orbicular to elliptic with a radial slit, entire, sinuate, dentate or toothed, hastate as seedling. Flowers floating or standing clear of water. Sepals usually 4, usually green outside, sometimes flecked with purple or pink; margins membranous, coloured as petals. Petals numerous, lanceolate to spathulate, variously coloured; gap between petals and stamens present or absent. Stamens numerous; filaments either ± cylindrical and membranous, or flattened and either tough or membranous; anthers dehiscing introrsely or latrorsely; apical appendage present or absent. Ovary half inferior. Fruit globose, drawn beneath water by coiled peduncle. Seeds arillate, glabrous or hairy; testa comprised of numerous interlocking cells.
Perennial, with vertical tubers. Leaves alternate, submerged, sometimes floating; petiole sheathing at base; submerged lamina sagittate to hastate, with lobes usually free, entire and crispate; floating lamina elliptic, entire, slightly undulate. Flowers solitary, standing clear of water. Sepals 4, obtuse; abaxial surface pink. Petals present or absent, oblong-elliptic, obtuse, light to dark purple, with a gap between petals (sepals) and stamens. Stamens numerous; filaments membranous, flattened; anthers lateral, dehiscing latrorsely; apical appendage absent. Ovary half-inferior. Fruit an ovoid berry. Seeds arillate, glabrous, with fine longitudinal striations.
Sep 4, green; pet numerous, white or pink, inserted on the ovary; stamens numerous, inserted on the ovary; inner stamens with linear filament and long anther, the outer with progressively widened, petal-like filament and shorter anther; stigmatic disk with 6–30 radiating lines; lf-blades floating, rotund or elliptic with a basal sinus; petioles and peduncles with 4 large air-passages. (Castalia) 30, widespread
Rhizomatous. Lvs floating or emergent, entire, deeply cordate, stipulate, reddish beneath, with anastomosing lateral veins. Sepals 4-(5), green beneath. Petals white or yellow, rarely red, pink or blue; outer petals > sepals. Ovary semi-inferior. Seeds arillate.
Leaves large or medium, floating, emergent or submerged, lamina suborbicular to elliptic, deeply cordate, peltate, palmatinerved.
Stamens perigynous; filaments petaloid; anthers obtuse or appendiculate owing to a prolongation of the connective.
Sepals 4 (sometimes appearing more numerous owing to the presence of ± sepaloid petals).
Stamens numerous, inserted with the petals on the side of the receptacle
Seeds small, surrounded by a pulpy, sack-like aril open at the top.
Robust or delicate aquatic herbs, rhizome often tuberous.
Leaves deeply cordate with numerous radiating nerves
Ovary many-celled, with radiating sessile stigmas
Petals indefinite in 2 or more series
Fruit fleshy, ripening under water.
Seeds numerous, immersed in pulp.
Carpels numerous, pluriovulate.
Petals 5-numerous.
Rhizome perennial
Sepals 4
