Perennials or subshrubs, 40-200 cm. Stems (erect, stout) glabrous, glaucous. Leaves spreading-ascending to erect; blades 3- or -5-nerved, linear, 82-100 × 4.3-10 mm, lengths 10-27 times widths, gradually to abruptly reduced distally, herbaceous to firm-herbaceous, margins scabrous, apices abruptly acute to acuminate, faces ± gland-dotted (18-56 dots per mm²), adaxial and vein axils often sparsely hairy. Heads mostly pedunculate, in relatively narrow, elongate arrays 33-60% of plant heights (often interrupted and with multiple levels). Involucres campanulate, 3.7-4.9 mm. Phyllaries stramineous, sometimes green-tipped, outer narrowly lanceolate, inner linear (firm), apices acute to acuminate. Ray florets (15-)17-22(-28). Disc florets (7-)9-11(-18); corollas 3.1-4.2 mm. 2n = 18.
Flowering Jul-Nov. Moist to wet soils of streambeds, lake shores, and fresh to saline marshes; 0-1600 m; B.C.; Ariz., Calif., Colo., Idaho, Mont., Nebr., Nev., N.Mex., Oreg., Utah, Wash., Wyo.; Mexico (Baja California).