Parry’s arnica, nodding arnica

Arnica angustifolia Vahl subsp. eradiata A. Gray, Proc. Acad. Nat. Sci. Philadelphia 15: 68. 1864; A. parryi A. Gray subsp. sonnei (Greene) Maguire; A. parryi var. sonnei (Greene) Cronquist

Plants 15–50(–60) cm. Stems simple or branched among heads. Leaves (2–)3–4 pairs, basal and cauline (basal usually withered by flowering, petiolate or subsessile, blades ovate or nearly round to oblong-ovate, much smaller than cauline; sterile rosettes often present, proximal cauline often crowded toward stems bases); petiolate; blades broadly to narrowly lanceolate, oblong-ovate, ovate-lanceolate, or round, 4–22 × 1–6 cm, (bases obtuse or cuneate to truncate) margins usually entire, sometimes sparsely denticulate, faces scantily to moderately pilose (hairs white), adaxial sparsely stipitate-glandular (distal cauline leaves sessile, extremely reduced, nearly linear to narrowly elliptic-lanceolate). Heads (1–)3–9(–14; often nodding in bud). Involucres turbinate to narrowly campanulate. Phyllaries 8–20, linear to narrowly lanceolate. Ray florets usually 0 (sometimes peripheral florets pistillate; corollas yellow, laminae rudimentary). Disc florets 20–50; corollas yellow (1 or more lobes sometimes expanded, giving appearance of laminae); anthers yellow. Cypselae brown to black, 4–7 mm, glabrous or sparsely stipitate-glandular to densely hirsute; pappi usually stramineous, rarely tawny, bristles barbellate to ± subplumose. 2n = 38, 57, 76.

Flowering May–Sep. Open conifer forests to alpine meadows; 500–3800 m; Alta., B.C., Yukon; Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.