短序黑三棱 duan xu hei san leng

Sparganium manshuricum D. Yu.

Stems emersed, erect, 20-50 cm tall. Leaves 30-56 cm, lower keeled or trigonous on abaxial side. Racemes 6-15 cm; male heads 1-3, not separate from female ones; female heads 3 or 4(-8), relatively near each other, lowest one pedunculate. Male flowers: perianth segments ca. 1.5 mm, serrate-lobate at apex; filaments 3-3.5 mm; anthers oblong, ca. 1 mm. Female flowers: perianth segments 2-2.5 mm, lobate at apex; ovary fusiform, with short stalk; styles short; stigmas ca. 0.5 mm. Fruit broadly fusiform, ca. 3 mm. Fl. and fr. Jun-Sep. 2n = 30.

Margins of lakes, swamps, and slow-moving rivers. Heilongjiang, Jilin, Liaoning, Nei Mongol, Xizang, Yunnan [Japan, Mongolia, Russia; Europe, North America].

A specimen with seven or eight female heads and larger flowers from Heilongjiang, which was described as Sparganium manshuricum (Bull. Bot. Res., Harbin 12: 255. 1992) mainly according to some quantitative characters, perhaps represents a local variant suite of specimens rather than a distinct taxon.