10. Pycreus setiformis (Korshinsky) Nakai, Bot. Mag. (Tokyo). 26: 201. 1912.
东北扁莎 dong bei bian suo
Cyperus setiformis Korshinsky, Trudy Imp. S.-Peterburgsk. Bot. Sada 12: 405. 1892.
Annuals. Roots fibrous. Culms tufted, 5-30 cm tall, slender, 3-angled, smooth, with a few leaves basally. Leaves shorter than culm; sheath slightly reddish brown; leaf blade 0.3-1.5 mm wide, flat. Involucral bracts 1-3, usually longer than inflorescence, spreading, sometimes basalmost bract erect. Inflorescence a simple anthela; rays very short, each with 1 to several spikelets. Spikelets obliquely spreading, oblong to narrowly oblong-ovoid, 0.5-1.5 cm × 3-4 mm, compressed, 8-16-flowered; rachilla flexuose, narrowly winged. Glumes purplish red to reddish brown on both surfaces, slightly densely imbricate, ovate, ca. 2.5 mm, 3-veined, keel green, margin white hyaline, apex obtuse. Stamens 2; anthers linear; connective apex prominent beyond anthers. Style long; stigmas 2, slightly short. Nutlet black, broadly obovoid, ca. 1.5 mm, biconvex, inconspicuously transversely undulately striate to nearly reticulately striate, apex mucronate. Fl. and fr. Jul-Sep.
Meadows, wet sandy areas. Heilongjiang, Jilin, Liaoning, Nei Mongol [Japan, Korea, Russia (Far East)].