1. Menyanthes trifoliata Linnaeus, Sp. Pl. 1: 145. 1753.
睡菜 shi cai
Rhizomes usually in mud but sometimes floating. Petiole erect, 12-20(-30) cm; leaf blade base vaginate; leaflets elliptic, 2.5-4(-8) cm, base cuneate, margin entire or crenulate, apex obtuse, midvein distinct. Inflorescences many flowered; racemes including scape 30-35 cm; bracts 5-7 mm, margin entire, apex obtuse. Pedicel spreading, 1-1.8 cm. Calyx 4-5 mm; lobes ovate, apex obtuse. Corolla white, tubular, 1.4-1.7 cm, outside glabrous, inside long fimbriate pilose; lobes elliptic-lanceolate, 7.5-10 mm, apex obtuse. Filaments linear, 5.5-6.5 mm; anthers sagittate, 1.8-2 mm. Styles linear, short styles 6-7 mm, long styles 1-1.2 cm; stigma lobes oblong. Capsules globose, 6-7 mm in diam. Seeds orbicular, 2-2.5 mm in diam., smooth. Fl. and fr. May-Jul.
Swamps, growing in mud and in open water; 400-3600 m. Guizhou, Hebei, Heilongjiang, Jilin, Liaoning, Sichuan, Xizang, Yunnan, NE Zhejiang [Japan, Kashmir, Mongolia, Nepal, Russia; N Africa, N America, C and SW Asia, Europe].