Common names: duck lettuce, santawaa, water plantain

Family: Hydrocharitaceae

Could be confused with: Aponogeton, Damasonium, Echinodorus.

Native distribution: Africa, Asia, Australia and South America.

Species cultivated:
Ottelia alismoides (L.) Pers. (Asia to Australia)
O. mesenterium (Hallier fil.) den Hartog (Indonesia)
O. ovalifolia (R. Br.) Rich. (Australia)
O. ulvifolia (Planch.) Walp. (Africa, Madagascar)

Adventive distribution: Ottelia alismoides is introduced in several states in the southern United States. Ottelia ovalifolia is introduced in New Zealand; its presence in New Caledonia is not confirmed.

Weed status: Ottelia alismoides is an aquatic weed on the U.S. federal noxious weed list.

Habit: Large, submersed or floating, attached rosette plant.

Brief description: Annual or perennial. Monoecious or dioecious. Stem typically compact, roots unbranched. Leaves in a basal rosette, sheathed at base, juvenile leaves usually sessile, mature leaves numerous, often petiolate, submersed and/or floating; mature leaf blade linear, reniform to orbicular, veins parallel or palmate; base rounded to cordate; margin entire or undulate. Spathe of 2 united bracts, often winged or ribbed. Flowers unisexual or bisexual; female and bisexual flowers sessile, solitary; male flowers numerous, pedicellate, emerging from spathe; sepals 3, green; petals 3, conspicuous, yellow, purple, white or pink, or reduced in cleistogamous flowers. Dispersal by numerous seeds.

Natural habitat: Usually in slower waters of rivers, lakes and ponds.

Additional comments: Ottelia contains 21 species; 13 species in Africa, seven in Asia and Australia and a single species in South America. A great deal of taxonomic confusion is associated with this genus due to the high degree of polymorphism in several species, especially O. alismoides. Although robust plants of Ottelia occur in the wild, only a few species (or varieties) are suitable for aquarium or pond cultivation, and they remain difficult species to maintain in permanent culture.