Stout monoecious perennial aquatic or marsh herb. Stems 25–60 cm tall, pilose, rarely glabrous. Submerged leaves in whorls of 5–8, ovate, pectinate, with 12–20 pinnae, lamina 15–30 mm long; emergent leaves in whorls of 6–8, the uppermost terete, the lower ones broadly lanceolate, shortly pectinate with 6–8 pinnae, lamina 5–18 mm long. Bracteoles of male flowers lanceolate to ovate, 0.6–0.7 mm long, entire; of female flowers smaller. Flowers 4-merous, sessile, solitary. Male flowers: sepals ovate to oblong, 0.6–0.8 mm long; petals 2–2.6 mm long, tardily caducous, cream to reddish brown or purplish; stamens 8. Female flowers: sepals and petals absent; ovary 4-locular; styles filiform, reflexed; stigmas white. Fruit cubiform, yellow-brown to deep red; mericarps cylindrical, tapering slightly to obliquely truncate apex, echinate-muricate.
Home