A family of aquatic or wetland (bog) herbs that have creeping rhizomes or tufted root-stocks. They are mainly perennial. They are related to Gentianaceae but are found in different habitats and have leaves that are mostly alternate. The regular flowers are borne in cymes or dense clusters. The corolla is 5-lobed, with valvate lobes when in bud. The sepals (which remain in the fruit) and the united petals are pink, yellow, or white, with a fringe of hairs in the flower. The stamens are attached to the corolla tube. The ovary is superior, with 1 locule and several ovules, the style is simple and forked. The fruit is a fleshy nut or dry capsule which is often dehiscent. The seeds contain much endosperm and are often winged. Menyanthes (buckbean) has trifoliate leaves; Nymphoides (fringed water lily) has simple, round leaves. There are 5 genera, with some 40 species, widespread in the world, although 2 of the genera are restricted to the northern hemisphere and 2 to the southern hemisphere. Some species are garden ornamentals, and species of Menyanthes are used in medicine.
Subjects: Plant Sciences and Forestry.