San Leng

Sparganium stoloniferum is a robust aquatic to semi-aquatic perennial herb of the family Typhaceae (formerly Sparganiaceae), native to wetlands, ponds and slow streams across temperate East and Central Asia. From a creeping, swollen, starchy rhizome it produces stout erect stems 60-150 cm tall bearing linear, triangular-keeled leaves 40-90 cm long that emerge above the water surface. The monoecious inflorescence is a branched panicle of globose flower-heads, the upper smaller heads staminate and the lower 3-5 larger heads pistillate, maturing into burr-like clusters of beaked achenes 8-10 mm long. The medicinally used part is the conical, fusiform, peeled rhizome (sometimes called a corm), 2-6 cm long, hard, heavy and yellowish-white internally with a bitter, acrid taste.