Nymphoides crenata, commonly known as wavy marshwort, is an aquatic perennial herb of the family Menyanthaceae endemic to Australia, found in all mainland states and the Northern Territory[1] [2] [3]
It is a stoloniferous, floating, perennial with stems up to 3 m long. The petioles of the basal leaves are from 8–42 cm long. The leaf lamina are ovate to circular, and deeply cordate and vary from 3 to 15 cm in length. The stem leaves are smaller, and sometimes kidney-shaped. The flowers heterostylous, (see the gallery) and there can be from 8 to14 in clusters subtended by 1–4 stem leaves, or sometimes in spaced pairs along a short inflorescence. The calyx is from 5.5 to 16 mm long and the corolla from 20 to 50 mm in diameter. There are usually 4 lobes (sometimes 4 or 6) and there are usually 5 stigmas (but from 2-5).
It grows on floodplains,[4] in swamps, lagoons, irrigation channels, and also in temporarily inundated depressions, and in slow-flowing streams where the depth of the water is up to about 1.5 m deep, usually on mud, and it will persist on drying mud.
Nymphoides crenata was first described as Limnanthemum crenatum in 1854 by Ferdinand von Mueller.[5] In 1891, Otto Kuntze transferred it to the genus, Nymphoides.[6]