Rau om

There are some 40 species of aromatic aquatic or marsh-dwelling annuals and perennials in this genus, which occurs in the Old World tropics. They creep when growing in boggy ground, growing erect when submerged. About a dozen species have finely divided submerged foliage, making attractive specimens for aquaria. Several are used locally for medicinal or culinary purposes, but only one species, Limnophila aromatica, is in more general circulation. It was introduced to N America in the 1970's by refugees from Vietnam, ans is often stocked by Asian food stores. The distinctive flavor of L. aromatica is described as "floral". Other species include L. gratioloides, which has a camphor-lemon aroma, and is given in India for dysentery, or made into a liniment with coconut oil to treat elephantitis. Limnophila is derived from the Greek limne, "bog", and philos, "friend", referring to the marsh-loving nature of the genus.

Aquatic annual with spongy, pale green stems, rooting from the nodes, and smooth, bluntly lanceolate leaves, to 2.5cm (1in) long, which have serrate margins. Small, pale violet-pink flowers appear singly or in short, leafy, axillary spikes, followed by two-valved capsules, containing angular, shiny seeds.

Common Name:	Rau om
Other Names:	Berema, Ngô om, Rau ngô, Rice paddy herb, swamp leaf
Botanical Name:	Limnophila chinensis subsp. aromatica syn. L. aromatica
Genus:	Limnophila
Family:	Scrophulariaceae
Native Location:	S Asia, Australia
Cultivation:	Damp to wet soil, or shallow water, in sun or partial shade.
Propagation:	By seed sown when ripe; by stem tip cuttings or division during the growing season.
Harvest:	Sprigs of foliage are cut as required and used fresh for flavoring, poultices, and decoctions.
Height:	30cm (12in)
Width:	Indefinite
Hardiness:	Min. 20°C (68°F)
Parts Used:	Leaves, stem tips.
Properties:	An aromatic herb with laxative, expectorant, and healing effects.
Medicinal Uses:	Internally, in Sri Lanka, for fevers, and externally as a poultice for sores.
Culinary Uses:	Leafy stems are used to flavor soups, stews, curries, and sweet-and-sour dishes, especially in Vietnamese cuisine.
Bibliography:	Encyclopedia of herbs by Deni Brown Copyright © 1995, 2001 Dorling Kindersley Limited. pg 262