Perennial monoecious aquatic herb. Stems 0.3–2 m long. Leaves in whorls of 4 or 5; submerged leaves ovate, pectinate, with 10–18 pinnae, lamina 1.2–2.5 cm long; emergent leaves ovate, entire or denticulate, lamina 4–8 mm long. Bracteoles oblong, 1–2 mm long, green to purple. Flowers 4-merous, sessile, solitary. Male flowers: sepals deltoid, 0.3 mm long; petals 2.6–3.5 mm long, caducous, green to purple. Female flowers: sepals absent; petals vestigial; ovary 4-locular; styles conical; stigmas smooth to minutely papillose, dark red. Fruit globose, deep purplish black; mericarps ovoid, 2–2.5 mm long, rounded, smooth to minutely punctate.
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