Biennials or perennials, (10-)20-80(-100) cm (monocarpic; sometimes with sparingly branched, woody caudices). Stems 1-3(-15), usually purple-red-tinted proximally, sometimes purple-red-tinted throughout, branched distally, ± hairy. Leaves: blades simple or lobed (lobes 3-9), ± hairy, gland-dotted (basal leaf bases ± long-villous-woolly); mid leaves lobed (lobes 3-5, terminal lobes 1-2.5 mm wide). Heads (1-)7-45(-80) per plant, in paniculiform to corymbiform arrays. Peduncles (2-)3.5-8(-13) cm, ± hairy. Involucres subhemispheric to hemispheric, 8-10 × 10-17 mm. Phyllaries in 2 series, unequal; outer 8-15, basally connate 1/3-1/2 their lengths (moderately to strongly keeled), lanceolate, 4.5-8.9 mm, apices acuminate to acute; inner 14-22, obovate to oblanceolate, 4.1-6.8 mm, apices acuminate to mucronate. Ray florets 9-14; corollas yellow, 10.2-17(-21.5) × 4-7.5(-9.2) mm. Disc florets 30-150+; corollas 2.7-4.8 mm. Cypselae narrowly obpyramidal, 1.7-3.7 mm; pappi of 5-6(-8) obovate, aristate scales 1.3-3.3 mm. 2n = 30. Flowering May-Jun(-Sep). Roadsides, open areas, edges of juniper-pine forests; (1000-)1500-2500(-3500) m; Ariz., Calif., Idaho, Nev., Oreg., Utah. Some plants of Hymenoxys cooperi, mostly 10-40 cm with mostly 1-6 heads, have been called var. canescens.
General: Biennial or short-lived perennial, 10-100 cm tall; stems 1 to several, erect, branched above, often tinged purple- red at the base or throughout, nearly glabrous or bearing fine white hairs; caudex woody, sparingly branched; taprooted. Leaves: Basal and cauline, alternate, simple or lobed (lobes 3- 9), 2-10 cm long, gradually reduced above, the lobes linear, the terminal one 0.5-2 mm wide, more-or-less hairy and gland-dotted. Flowers: Heads solitary, occasionally in panicle-like arrays; peduncles more-or-less hairy, densely tomentose below the heads; involucre hemispheric to broadly campanulate, 13- 20 mm long, 23-32 mm wide, occasionally silky-villous; phyllaries in 2 series, unequal, the outer series connate only slightly (for about 1/5 their length); ray flowers 13-15, 13-26 mm long, yellowish; disk flowers 100-250 or more, 5.7-7.4 mm long, yellow; flowers April-October. Fruits: Achene, narrowly obpyramidal, 1.7-3.7 mm long, densely pubescent; pappus of 5-6 obovate, bristle-like scales. Ecology: Dry, open slopes, ridges, roadsides, edges of juniper- pine forests, often in sandy soil; 600-2400 m (2000-8000 ft); Coconino, Mohave, and Yavapai counties; western U.S. Notes: Hymenoxys lemmonii (Lemmon-s rubberweed) is similar to H. cooperi, but is distinguished by having somewhat succulent and glabrous to sparsely hairy gland-dotted leaves. Uncommon in our range, it can be found in moist alkaline meadows. The Hopi make tea, dye, and prayer sticks from H. cooperi. Editor: Springer et al. 2008