Perennials, 7-34 cm (polycarpic; usually with highly branched woody caudices). Stems 1-20(-30+), usually green throughout, rarely purple-red-tinted proximally, branched distally, glabrous or ± hairy. Leaves: blades simple or lobed (lobes 3-7), glabrous or ± hairy, gland-dotted (basal leaf bases densely long-villous-woolly); mid leaves lobed (lobes 3-5, terminal lobes 0.7-2 mm wide). Heads 5-300+ per plant, in corymbiform arrays. Peduncles 1-5 cm, ± hairy. Involucres campanulate, 7-11 × 7-14 mm. Phyllaries in 2 series, unequal; outer 8-13, obovate to ovate to lanceolate, basally connate 1/2 their lengths, 3.5-8 mm, apices acuminate to acute; inner 8-18, obovate, 3-8 mm, apices mucronate. Ray florets 7-14; corollas yellow, 7-17 × 3-6 mm. Disc florets 25-75+; corollas 3-5 mm. Cypselae narrowly obpyramidal, 2-3 mm; pappi of 4-8 obovate to lanceolate, aristate scales 1.8-3.5 mm. 2n = 30.
Springer et al. 2008, Heil et al. 2013, FNA 2006
General: Perennial herbs, 10-35 cm tall, from a branching woody caudex and stout taproot; stems mostly 5-20 per plant, erect, slender, branched above, usually green throughout, rarely tinged with purple-red at the base; herbage glabrous to pubescent, with long soft hairs tufted in the axils of persistent leaf bases. Leaves: Basal leaves sometimes persistent until flowering; stem leaves alternate, abundant; blades narrowly linear and/or lobed, 2-15 cm long, glabrous to sparsely pubescent, gland- dotted; lobes, if present, 3-7 per leaf, linear-filiform, 1-2 mm wide. Flowers: Flower heads yellow and radiate, arranged in panicles of up to 12 flower heads; peduncles sometimes tomentose near the apex; involucres hemispheric to broadly campanulate, 12-17 mm long and 20-25 mm wide, the bracts (phyllaries) in 2 series, these nearly equal; the outer series of phyllaries united at the base; the inner series of phyllaries not united at the base, equalling or surpassing the outer series in height; ray flowers 7-14 per flower head, the laminae (ray petals) 7-23 mm long, yellow-orange to orange, the tips 3- or 4- lobed; disc flowers 25-75 or more per flower head, yellow. Fruits: Achenes narrowly obpyramidal, 2-4 mm long, covered with long soft hairs; topped with a pappus of 5 obovate, bristle-like scales, these 2 mm long. Ecology: Found in open habitats, forest edges, and roadsides, from 4,500-10,500 ft (1372-3200 m), flowers May-October. Distribution: NM and AZ, north to MT and adjacent s CAN. Notes: This is a fairly common forest and woodland understory species. Look for a perennial herb with a branching woody caudex; filiform leaves, often in a basal tuft as well as lining the stems; and yellow radiate flower heads. Arizona and New Mexico specimens are var. floribunda, with many flower heads per plant, up to 300 or even more, involucres 7-8 mm high and 7-9 mm wide, and ray corollas 7-11 mm long. H. rusbyi differs from this species in its wider leaf lobes, 2-4 mm wide, simple to only moderately branched caudex, and slightly smaller flower heads, 4-8 mm wide. Ethnobotany: Chewed roots are applied to sores and rashes, and are also used as chewing gum. The flowers provide a yellow dye for wool. Etymology: Hymenoxys comes from Greek hymen, meaning membrane, and oxys, meaning sharp or sharp pointed, referring to the awned pappus scales; richardsonii honors Sir John Richardson (1787-1865), English naturalist and Arctic explorer. Synonyms: Actinella richardsonii, Picradenia richardsonii, Actinella richardsonii Editor: AHazelton 2017