Alismataceae

Alismataceae, commonly known as the water-plantain family, is a small family of aquatic and marsh-dwelling flowering plants in the monocot order Alismatales. The family comprises about 12–16 genera and around 100 species, distributed worldwide in wetlands, riversides, ponds, and other freshwater habitats in temperate and tropical regions.

Plants in the family are herbaceous perennials with rhizomes or tubers, adapted to aquatic or semi-aquatic life. Leaves are diverse in form, often basal, with blades that may be simple, sagittate (arrowhead-shaped), or reniform, and some species have floating leaves. The flowers are generally small and bisexual, arranged in inflorescences such as spikes or panicles; the perianth is typically six-parted, and the fruits are dry and often form capsules or achenes.

Notable genera include Alisma (water-plantain), Sagittaria (arrowheads), Damasonium, Limnocharis, and Echinodorus, the latter of which contains popular cultivated aquarium plants. Several species have horticultural or medicinal value; for example, Alisma plantago-aquatica has a history of use in traditional medicine, and some Echinodorus species are grown as ornamentals.

Taxonomically, Alismataceae is placed within the order Alismatales. Its members are characterized by aquatic or marsh-adapted morphology and reproductive structures consistent with monocotyledonous lineages. Ecologically, the family contributes to wetland biodiversity and can play a role in water navigation, sediment stabilization, and habitat provision for aquatic fauna.