Nodding Arnica

Plants 8–35 cm. Stems (1–3 together) usually simple, rarely branched (moderately to densely hairy, hairs translucent with purple septa). Leaves (2–)3–5(–6) pairs, usually crowded toward stem bases; petiolate or sessile (petioles short-winged); blades elliptic, lanceolate, or broadly oblanceolate, 3–10 × 1–2.5 cm, margins usually entire proximal to mid blade, subentire to denticulate distally, apices acute to obtuse, faces: abaxial paler and often glabrous, adaxial slightly hairy. Heads 1 (nodding). Involucres turbinate-campanulate (bases moderately villous, hairs brownish). Phyllaries 11–15, lanceolate to elliptic (apices obtuse, tips blunt, callous). Ray florets 8–13; corollas yellow (laminae 14–20 mm). Disc florets: corollas yellow; anthers dark purple. Cypselae brown, 5–6 mm, sparsely strigose (hairs simple, apically pointed) or glabrous; pappi tawny, bristles barbellate. 2n = 38, 57, 76.

Arnica angustifolia Vahl var. lessingii Torrey & A. Gray, Fl. N. Amer. 2: 449. 1843; A. lessingii subsp. norbergii Hultén & Maguire