Hymenoxys cooperi

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, glanddotted (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.

Phenology: Flowering May–Jun(–Sep).
Habitat: Roadsides, open areas, edges of juniper-pine forests
Elevation: (1000–)1500–2500(–3500) m

Ariz., Calif., Idaho, Nev., Oreg., Utah.

Discussion

Some plants of Hymenoxys cooperi, mostly 10–40 cm with mostly 1–6 heads, have been called var. canescens.

Selected References

None.

Lower Taxa