Riceweeds en - Convolvulaceae - Ipomoea aquatica Forssk.

IPOAQ

Convolvulaceae

Ipomoea aquatica Forssk.

Broadleaf

A trailing annual or, under suitable condition, a stoloniferous perennial herb of wet place with alternate, triangular-shaped leaves and large funnel-shaped, solitary flowers, purple, pink or white in colour.

Aquatic/semiaquatic creeping herb.

Roots at the lower node.

Stem up to 3 m long is slender, hollow and smooth, free branching, long trailing and milky sap.

The leaves are alternate, simple, variable in shape, oblong, free or oblong-lanceolate or sometimes lobed. They are generally about 14(-15) cm long and 8(-9) cm wide, acute at the apex, entire at the margins and heart-shaped at the base with petioles about 3-15 cm long.

The inflorescence is made up of solitary flowers in leaf axils.

The flowers are arise in the leaf axils, also on long stalks, and are usually about 5 cm long. The sepals are 6-12 mm long, the corolla has a narrow tube, to which the 5 stamens are attached, and is expanded above with a 5- pointed rim.

The fruit are 1 cm long ovoid capsules that are 4-seeded.

The seeds are brown, about 7 mm long and 4 mm wide and are densely.

It is reproduces mainly from vegetative stems and stolons and rarely from seeds.

A common aquatic weed of poorly drained soils, often found in rice paddies throughout West Africa. I. aquatic occurs on swampy ground and in stagnant water in all the East African countries up to an altitude of 1200 m.

Widespread as a swamp weed in all tropical and many subtropical lowland areas.

It is a common as a weed of rice fields, especially in Tanzania.

Benin: Frequent and usually abundant.
Burkina Faso: Rare and not abundant.
Cote d'Ivoire: Frequent but not abundant.
Kenya: Frequent but not abundant.
Mali: Frequent and usually abundant.
Ghana: Rare and not abundant.
Senegal: Rare but abundant when present.
Chad: Frequent and usually abundant.
Nigeria: Frequent and usually abundant.
Tanzania: Frequent and usually abundant.
Uganda: Rare but abundant when present.

Few observation on a control have been recorded but in Tanzania it is has been noted that, because of the presence of submerged stems and leaves, this weed increases in density following the use of such herbicides as propanil or bentazon in rice. Some control appears to be possible with oxadiazon.
Management options: http://www.afroweeds.org/network/pg/file/read/1902/general-guidelines-for-weed-management-in-lowland-rice

Young shoots and leaves of kangkong are collected for use as a leafy vegetable. Often the whole above-ground plants part of cultivated kangkong, including the tender hollow stems, is consumed. Kangkong can be stir-fried, steamed, boiled for a few minutes or lightly fried in oil and eaten in various dishes, it is often mixed with hot peppers and garlic, and prepared with meat or fish.in Asia the leaves are sometimes separated from stems, and the stems are cooked a bit longer. In Africa only the leaves of wild plants are consumed. The roots are occasionally eaten. Wild kangkong is often collected as folder for cattle and pigs. In Indonesia, kangkong is traditionally given at dinner to young children to make them quiet and help them to sleep well. In Asia it is used in traditional medicine. The sap is used as anemetic, purgative and sedative, and flower buds are applied to ringworm.

D.E. Johnson (1997). Les adventices en riziculture en Afrique de l'Ouest /Weeds of rice in West Africa. West Africa Rice Development Association, Bouaké, Côte d'ivoire. 68p.
Grubben, G.J.H. & Denton, O.A. (2004): Plant Resources of Tropical Africa 2: Vegetables. PROTA Foundation, Wageningen; Backhuys publishers, Leiden, Netherlands/CTA, Wageningen, Netherland. 333p.
G. W. Ivens (1989). Eastern Africa weeds control. Oxford University press, Nairobi. 171p
I. O. Akobundu and C.W. Agyakwa (1998). A handbook of West African Weeds. International Institute of Tropical Agriculture, Ibadan, Nigeria 14p

Environmental Council of Zambia: http://www.necz.org.zm/iaszambia/ipomoea.html
Global Invasive Species Database: http://www.issg.org/database/species/ecology.asp?fr=1&si=477
Pacific Island Ecosystems at Risk (PIER): http://www.hear.org/pier/species/ipomoea_aquatica.htm