Perennials, 30–75 cm tall, rhizomatous, forming loose stands. Rhizome short-creeping to long-creeping, 2–3 mm in diam., pale brown, not swollen. Stem usually densely papillose-rugulose, rarely ±smooth. Cataphylls 1–2, pink to stramineous, acute; basal leaves 1–2, 20–30 cm long. Cauline leaves 1–2, 20–30 cm long, terete, perfectly septate (septa visible externally, prominent in dry condition), rugulose or rarely smooth, unitubular; tip acuminate; sheaths broadly bordered; auricles 1–4.9 mm long, rounded, membranous. Lower bract herbaceous, stramineous, lanceolate to linear, 1.2–3.2 cm long, shorter than the inflorescence, erect; other bracts stramineous, lanceolate, 4–6 mm long. Inflorescence diffuse, decompound, of 25–66 heads, usually 7–15 cm long, with main branches erect to erecto-patent and other branches often ±patent; heads semiglobose to obovoid, 6–10-flowered, 5–10 mm in diam. Tepals subequal, lanceolate, stramineous to brown, acuminate; outer tepals carinate, with prominent midrib, (2–) 2.5–3.4 mm long, stramineous-brown to castaneous, acuminate, with margins broad and membranous; inner tepals often slightly longer, flat, subacute to mucronate, (2–) 2.6–3.6 mm long, distally with broad membranous margins. Stamens 6, not exserted; anthers 0.6–1.0 mm long, c. 1.5 times as long as 0.5–0.7 mm filaments; style 0.5–0.6 mm long; stigmas 0.6–1.1 mm long. Capsules unilocular, tapering to a subulate tip from narrowly ovoid base, trigonous, (2.4–) 3–3.9 mm long, castaneous-brown, ±exceeding perianth. Seeds ellipsoid-ovoid, apiculate, 0.3–0.5 × 0.2–0.3 mm, pale brown, distinctly reticulate; appendages absent. 2n = 40, fide N.A.Harriman & D.Redmond, Rhodora 78: 735 (1976).
Restricted to California and northernmost NW Mexico. 76: CAL. 79: MXN.
76. CALIFORNIA: San Bernardino Co., San Gabriel Mtns, Cajon Ck, R.F.Thorne, C.W.Tilforth & al. 42164 (NSW); San Bernardino Mtns, S.B.Parish & W.F.Parish 1026 (PR); Kern Co., 3.2 km above Kernville, J.T.Howell 44112 (NY); San Diego Co., Cleveland National Forest, E slope Aqua Tibia Mt., D.L.Banks & S.Boyd 5 (NY); Sonoma Co., Laguna de Santa Rosa, R.Rubtzoff 4490 (NY); Tulare Co., Kaweah River at Three Rivers, J.T.Howell 50286 (NY); Los Angeles Co., Buckhorn Station, R.F.Thorne & L.E.DeBuhr 42239 (NSW).
Montane meadows, river beds, canyons, arroyos; 100–1600 m.
This species has rugulose stems and leaves throughout most of its range, but on the periphery of its range (in Mariposa, San Diego, and Sonoma Counties, California) the plants are smooth.