Pingue Rubberweed

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.

Picradenia richardsonii Hooker, Fl. Bor.-Amer. 1: 317, plate 108. 1833 (as richardsoni)

Hymenoxys biennis (A. Gray) H. M. Hall, Univ. Calif. Publ
Bot. 3: 204. 1907.
A ctinella Richardsoni A. Gray, Bot. Calif. 1: 394. 1876. Not A. Richardsoni Nutt. 1841.
Actinella biennis A. Gray, Proc. Am. Acad. 13: 373. 1878.
Picradenia biennis Greene, Pittonia 3: 272. 1898.
Hymenoxys canescens biennis Cockerell, Bull. Torrey Club 31: 482. 1904.
A biennial, with a strong tap-root; stems solitary, 3-5 dm. high, branched above, puberu. lent with broad, scale-like hairs, striate; leaves 3-8 cm. long, more or less pubescent with similar hairs and glandular-punctate, divided into linear-filiform divisions, the basal ones numerous and crowded, the stem-leaves with smaller fasciculate ones in their axils; heads several or many, corymbose; peduncles 5-10 cm. long; involucre hemispheric or depressed, 5 mm. high, 10-15 mm. broad; outer bracts 10-15, lanceolate, united only at the base, acute, carinate only at the base; inner bracts ovate, acute, only slightly erose; ligules 8-10 mm. long, 2.5-3 mm. wide; disk-corollas 4 mm. long, densely glandular; tube 1 mm. long; achenes 2.5 mm. long, densely hirsute; squamellae ovate, 1.5 mm. long, abruptly acuminate into an awn-tip.
Type locality: Mokiak Pass, Arizona. Distribution: Arizona and Utah.

Hymenoxys biennis is a North American species of flowering plant in the daisy family. It is native to the state of Utah in the western United States.