Anyhoo, here's the low-down from Wiki: http://en.wikipedia.org/wiki/Ipomoea_aquatica
"Ipomoea aquatica is a semi-aquatic tropical plant grown as a leaf vegetable. It is known in English as Water Spinach, Water Morning Glory, Water Convolvulus, or by the more ambiguous names "Chinese spinach" and "swamp cabbage". It has many other names in other languages. It is found throughout the tropical and subtropical regions of the world; it is not known exactly where it originated. [although some sources say it originated from Taiwan and S. China]. Ipomoea aquatica grows in water or on moist soil. Its stems are 2–3 metres (7–10 ft) or more long, rooting at the nodes, and they are hollow and can float. The leaves vary from typically sagittate (arrow-head-shaped) to lanceolate, 5–15 centimetres (2–6 in) long and 2–8 centimetres (0.8–3 in) broad. The flowers are trumpet-shaped, 3–5 centimetres (1–2 in) diameter, usually white in colour with a mauve centre. The flowers can form seed pods which can be used for planting.Ipomoea aquatica is most commonly grown in East and Southeast Asia. Because it flourishes naturally in waterways and requires little if any care, it is used extensively in Malay and Chinese cuisine, especially in rural or kampung(village) areas. It has also been introduced to the United States where its high growth rate has caused it to become an environmental problem, especially in Florida and Texas. It has been officially designated by the USDA as a "noxious weed" (the term "noxious" refers to its effect on the environment, not to any toxicity). In Chinese cuisine (Chinese: 空心菜; literally "hollow vegetable") there ways numerous ways of preparation, but a simple and quick stir-fry either plain or with minced garlic is probably the most common. In Cantonese, the water spinach is known as 蕹菜 (Jyutping: ung3 coi3, sometimes transliterated as ong choy). In Cantonese cuisine, a popular variation adds fermented bean curd. In Hakka cuisine, yellow bean paste is added, sometimes along with fried shallots. The vegetable is also extremely popular in Taiwan, where it grows well."
Back in the day, my mom would typically saute these greens in just some vegetable oil and a bunch of chopped garlic. So here's my rendition of her version. And in case you're wondering, it tastes kinda like spinach and also cooks down to a fraction of its original volume like spinach.