Alternative names: Not Applicable

Description:
Annual or perennial herbs, often shortly rhizomatous; leaves alternate radical or cauline, exstipulate, simple (or trifoliolate outside Australia), erect or floating; petioles winged at the base; stems erect or floating, often stoloniferous.

Inflorescence a fascicle or panicle (or, not in S.Aust., a solitary flower or a raceme); flowers regular, bisexual, sometimes with styles of different lengths in different flowers (heterostylous); sepals usually 5 (in S.Aust.) or 4, more or less free or basally united, persistent; corolla with a short tube and usually 5 (in S.Aust.) or 4 spreading lobes, short-lived and breaking down as though dissolving; corolla-lobes valvate or induplicate-valvate in bud, usually with entire or laciniate side-wings and a transverse fringe of hairs or papillae near the base, sometimes hairy or keeled on the adaxial surface; stamens alternate to the corolla lobes, epipetalous; anthers 2-celled, oblong, introrse; ovary superior to semi-inferior, usually with 5 (in S.Aust.) or 4 nectary lobes at the base; placentas 2-5, parietal; style simple; stigmas 2-5, each a papillate wing or lobe.

Fruit a capsule (or, not in S.Aust., fleshy), ellipsoid to globular, indehiscent or apically 4-valved; seeds few to numerous, endospermic.

Distribution:  5 genera with about 49 species throughout tropical to cold temperate regions of the world.

Biology: No text

Uses: The Northern Hemisphere Menyanthes and some Nymphoides are ornamentals in garden ponds. In Australia N. crenata and N. indica are only minor weeds of irrigation channels and stock tanks but in Asian countries some Nymphoides are prominent weeds affecting irrigation, navigation and fish culture.

Taxonomic notes: J. Black (1926) Fl. S. Aust. and many other authors included Menyanthaceae in Gentianaceae. (H. I. Aston (1973) Aquatic plants of Australia; G. R. Sainty & S. W. L. Jacobs (1981) Waterplants of New South Wales).

Key to Genera:

1. Flowers in spaced pairs or in clusters along horizontal usually floating stems; capsules mostly indehiscent and submerged, sometimes dehiscing by valves on plants on mud	NYMPHOIDES 1.
1. Flowers in open panicles on erect to semi-erect stems; capsules aerial, opening by 4 apical valves	VILLARSIA 2.

Author: Prepared by Helen I. Aston