Distribution: Southest Washington and northeast Oregon, east to Utah, Minnisota and Texas.
Habitat: Wet, low ground, from the lowlands to moderate elevations in the mountains.
Flowers: June - August
Conservation Status: Review Group 1 in Washington (WANHP)
Coarse, herbaceous perennials from short, stout rhizomes, the stems loosely clustered, triangular, 6-15 dm. tall.
Stem leaves several, the blades flat, grass-like, 6-15 mm. wide and up to several dm. long, the sheaths greenish or pale.
Inflorescence a simple or compound terminal cyme, with very numerous, sessile spikelets 3-4 mm. long, in dense, often compound clusters that are at least 1 cm. thick; inflorescence subtended by several unequal, sheathless bracts, the largest of these about 1 dm. long; flowers subtended by translucent, greenish-black scales with a thickened, greenish or brownish midrib which is exerted as an awn 0.5 mm. long; perianth bristles usually 6, slender, no longer than the achene; stamens 3; style trifid.
Achenes unequally triangular, 1.0-1.2 mm. long.