Pinaleno Mountain Rubberweed

Perennials, 30–150 cm (poly-carpic, with sparingly branched, woody caudices). Stems 1–3, usually purple-red-tinted proximally, branched distally, glabrous or ± hairy. Leaves: blades simple or lobed (lobes 3–19+), glabrous or sparsely hairy, gland-dotted; mid leaves lobed (lobes 3–19+, terminal lobes 0.7–1.3 mm wide). Heads 25–400+ per plant, in paniculiform to corymbiform arrays. Peduncles 0.4–2 cm, glabrous or ± hairy. Involucres campanulate to narrowly campanulate, 5–7.5 × 2.2–4.5 mm. Phyllaries in 2 series, unequal; outer 3–5, basally connate ¹/2–³/4 their lengths, obovate to oblanceolate, 4–6 mm, apices acuminate, acute, obtuse, or rounded; inner 3–5, obovate to oblanceolate, 2.5–4.5 mm, apices acuminate, acute, obtuse, or rounded, sometimes mucronate. Ray florets 3–5; corollas yellow, extending beyond phyllaries, 3.4–6 × 1.7–4 mm. Disc florets 6–15 (functionally staminate); corollas 3–4 mm. Cypselae obconic, 1.7–3.5 mm (hairy, hairs straight or wavy); pappi 0, or of 2–6 ± lanceolate scales 1–2.5 mm.

Plummera ambigens S. F. Blake, J. Wash. Acad. Sci. 19: 276, fig. 1a–i. 1929

Hymenoxys ambigens is a species of flowering plant in the daisy family known by the common name Pinaleño Mountains rubberweed. It is native to the states of Arizona and New Mexico in the southwestern United States.

Hymenoxys ambigens is a perennial herb up to 150 cm (5 feet) tall. Leaves have very narrow lobes resembling branching threads. One plant can produce an array of 25–400 small yellow flower heads, each head with 3-5 ray flowers and 6–15 disc flowers.

Varieties Hymenoxys ambigens var. ambigens - Mescal, Pinaleño, and Santa Teresa Mountains in Arizona Hymenoxys ambigens var. floribunda (A.Gray) W.L.Wagner - Chiricahua, Dos Cabezas, Dragoon, Little Dragoon, and Mule Mountains in Arizona Hymenoxys ambigens var. neomexicana W. L. Wagner - Animas + Peloncillo Mountains in New Mexico