Ipomoea aquatica Forssk.
Common names: water-spinach, Chinese water-spinach, water morning-glory, swamp cabbage
Fruit a capsule, with 1–4 seeds. Seeds 3-sided, 4.5–5.5 mm long, 3.5–4.5 mm wide, 2.5–3.5 mm thick. Two ventral faces usually flat, less often slightly concave, back arched, ventral view outline broadly elliptic or ovate to nearly round, lateral view outline depressed ovate to D-shaped; cross section sector-shaped with margins +/– keeled. Testa dull, light to dark reddish-brown, occasionally dark grey. Surface often minutely stippled. Glabrous or sparsely covered (occasionally heavily covered) with short tawny hairs. Hilum ca. 1 mm wide, whitish, emarginate, slightly recessed and surrounded by an omega-shaped hilar ridge fringed with tawny hairs. Embryo folded; endosperm present.
Useful characters for seed identification within Convolvulaceae are size, shape, color, texture, and hilum type, size and color. The hilar ridge fringed with hairs may help to distinguish Ipomoea aquatica from other Ipomoea species.
Widely cultivated and naturalized in South and Southeast Asia including Japan and Korea, tropical Africa, Australia and the Pacific Islands, tropical South America, Central America and the United States.
Still to flowing waters, in moist, marshy locations, shallow waters of canals, pools, ditches, lakes, swampy lowlands, rice fields.
Ipomoea aquatica is an aquatic, semiaquatic or terrestrial trailing vine, up to 3 m long. The species is cultivated as a green vegetable in some Asian countries; its leaves and fleshy stems are eaten and fed to livestock in China and India. In the U.S., it is eaten by Asian Americans and can be found for sale as seeds or leafy greens. Ipomoea aquatica can be a problem plant as well. Its long, floating stems form dense mats (with other plants such as Eichhornia and Salvinia) that may impede water flow, interfere with fisheries, and inhibit passage in fresh water. A weed of rice and other crops in 60 countries, and in the U.S. it is considered a serious threat to Florida’s waterways and wetlands. Ipomoea aquatica can be spread by seeds, plant fragments or whole plants.