乌苏里荸荠 wu su li bi qi

Eleocharis mamillata H. Lindberg var. cyclocarpa Kitagawa; E. mamillata subsp. ussuriensis (G. Zinserling) T. V. Egorova.

Perennials, with rhizomes and slender stolons. Culms single or laxly to densely tufted, 7-70 cm tall, 2-4 mm thick, terete, longitudinally ribbed and subsulcate, obscurely transversely septate between longitudinal ribs. Leaf sheaths 1 or 2, basally purplish red, tubular, 5-10 cm, mouth obliquely to transversely truncate. Spikelet ovoid-cylindric to narrowly cylindric-ovoid, 10-20 × 2-6 mm, many flowered. Basal 2 glumes empty, each amplexicaul for ca. 1/2 of spikelet base; fertile glumes green medially and reddish brown to dark brown on sides, subtightly imbricate, becoming laxly imbricate, oblong-ovate to ovate-lanceolate, 3-4 × 1.3-1.5 mm, apical margin broadly hyaline, apex acute to subacute. Perianth bristles 4 or 5, longer than nutlet, densely spreading and curved retrorsely spinulose. Style less than 1 mm; stigmas 2. Nutlet yellowish initially then brownish when mature, broadly obovoid to globose-obovoid, 1-1.5 × 1-1.3 mm, biconvex, subsmooth, apex constricted; persistent style base submammiform, shortly conic, or depressed conic, slightly wider than long, ca. 1/4 as long and ca. 1/2 as wide as nutlet, subspongy. Fl. and fr. Jun-Jul.

Moist areas, marshes, meadows; 100-1800 m. Hebei, Heilongjiang, Jilin, Liaoning, NE Nei Mongol, Shanxi [Japan, Korea, Russia (Far East, Siberia)].