Alismaceae

Alismaceae, the water-plantain family, is a small family of monocotyledonous flowering plants in the order Alismatales. The most familiar genus is Alisma, with several species including Alisma plantago-aquatica (common water-plantain) and Alisma orientale (Asian water-plantain). In many modern classifications, Alisma is the sole core genus retained in Alismaceae, with other genera historically placed here assigned to related families within Alismatales.

Description: Members are herbaceous aquatic or marsh plants, usually rhizomatous. Leaves are often basal and blade shapes range from lanceolate to sagittate, sometimes floating. The flowers are small, collected in spike-like inflorescences, typically with three tepals and six stamens; the fruit is a dry, usually ovoid achene.

Distribution and habitat: Alismaceae species are distributed in temperate and subtropical regions worldwide, especially in wetlands, ponds, marshes, and river margins. They prefer still or slow-moving water.

Ecology and uses: Many species grow in wetland ecosystems and contribute to habitat structure. Alisma orientale is cultivated and used in traditional East Asian medicine; other species are occasionally grown ornamentally in water gardens. Some taxa are threatened by wetland drainage and habitat loss.

Taxonomy notes: The circumscription of Alismaceae has varied; molecular studies have led to reassignments of some genera to related families within Alismatales. The best-known species are from genus Alisma.