PLANT: Perennial, rhizomatous, aquatic or bog plants. LEAVES: simple or trifoliolate. INFLORESCENCE: racemes, cymes, or umbels. FLOWERS: perfect, regular; calyx deeply 5‑parted; corolla rotate or funnelform, 5‑lobed or parted; stamens 5, epipetalous; pistil 2‑carpelled, the ovary 1‑loculed, superior to partially inferior. FRUITS: capsules, sometimes tardily dehiscent. SEEDS: usually many, smooth or papillate. NOTES: 5 genera, ca. 30 spp., both tropical and temperate regions. REFERENCES: Mason, Charles T., Jr. 2001. Menyanthaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1).