Nevada arnica, Sierra arnica

Arnica tomentella Greene

Plants 10–50 cm. Stems simple. Leaves 2–3 pairs, mostly cauline (basal leaves often persistent on sterile rosettes); petiolate (petioles narrowly to broadly winged); blades elliptic to ovate, 3–8 × 2–4 cm, margins entire or denticulate, apices acute to rounded, faces stipitate-glandular. Heads 1(–3). Involucres campanulate-turbinate. Phyllaries 10–16, oblanceolate. Ray florets 6–14; corollas yellow. Disc florets: corollas yellow; anthers yellow. Cypselae dark gray, 6–9 mm, stipitate-glandular; pappi white or tawny, bristles barbellate to subplumose. 2n = 76.

Flowering Jul–Aug. Coniferous forests, meadows, rocky slopes; 1500–3000 m; Calif., Nev., Oreg., Wash.