Plants with young vegetative parts heavily mucilaginous. Leaves all floating, long petiolate; leaf blade broadly elliptic, venation radiate, margin entire. Flowers anemophilous, usually long pedunculate; perianth not showy. Sepals linear-oblong to narrowly ovate. Petals narrowly oblong, lacking basal auricles. Stamens 12--36(--51), opposite both sepals and petals. Pistils 6--18; ovules (1--)2; stigmas linear-decurrent. Fruit slightly to strongly fusiform; seeds ovoid, lacking tubercles.

Source: [
• 5
]. 

Herbs , young vegetative parts heavily coated with mucilage. Leaves floating; petiole long. Leaf blade elliptic. Flowers: sepals 3, not petaloid, linear-oblong to narrowly ovate; petals 3, linear-oblong, lacking auricles, base not clawed; stamens 18-36(-51), opposite both sepals and petals; pistils 4-18, simple, 1-locular; ovules (1-)2; stigma linear-decurrent. Fruits slightly to strongly fusiform. Seeds ovoid, tubercles absent. x = 40.

Source: [
• 6
]. 

"Sep somewhat petaloid, colored within; stamens 12–18, or reputedly to 36; filaments of 2 lengths; anthers introrse, pistils 4–8; submerged parts covered with a mucilaginous jelly; lvs alternate, mostly crowded near the summit, long-petioled, with floating, centrally peltate blade. Monospecific"

Source: [
• 7
]. 

Floating leaves peltate; submerged leaves absent

Source: [
• 3
]. 

Stamens 12–18

Source: [
• 3
]. 

Sepals and petals persistent in fruit

Source: [
• 3
]. 

Testa with cells of outer layer very characteristically elongated radially.

Source: [
• 3
]. 

Carpels 6–18

Source: [
• 3
]. 

Carpels 6–18.

Source: [
• 4
]. 

Stamens 12–18.

Source: [
• 4
]. 

Leaves floating and peltate, submerged dissected leaves lacking.

Source: [
• 4
]. 

Herbes'à rhizomes rampants, portant des tiges grêles, ramifiées, couvertes de mucilage.'Feuilles'alternes, toutes flottantes, peltées, à limbe entier.'Fleurs apparemment axillaires, solitaires, longuement pédonculées, hypogynes, ordinairement trimères, rougeâtres; étamines 12-18, anthères à 4 sacs polliniques; carpelles 4-20, libres, à stigmate simple; ovules 2-3.\n\t\t\t\tGenre monospécifique.

Source: [
• 9
].