海菖蒲 hai chang pu

Stratiotes acoroides Linnaeus f., Suppl. Pl. 268. 1782; Enhalus koenigii Richard.

Roots robust, 10-20 cm, 3-5 mm in diam. Leaves 0.3-1.5 m × 1-2 cm, veins 13-19, margin entire, apex obtuse. Peduncle of male inflorescences ca. 5 cm; bracts sessile, slightly keeled, midvein hairy; male flowers pedicellate; sepals white, oblong, ca. 2 mm; petals white, larger than sepals; stamens white, 1.5-2 mm. Peduncle of female flower to 50 cm, coiled and contracted after anthesis; bracts 4-6 × 1-2 cm, midvein keeled, apparently hairy; sepals reddish; petals white, strap-shaped, strongly folded, 4-5 cm × 3-4 mm, papillose; ovary ovoid, with long hairs. Fruit ovoid, 5-7 cm. Seeds angular, 1-1.5 cm in diam. Fl. May.

Submerged in shallow water along seacoasts. Hainan [Cambodia, India, Indonesia, Malaysia, Myanmar, Philippines, Sri Lanka, Thailand, Vietnam; Africa, Australia].