Arnica longifolia
in S. Watson, Botany (Fortieth Parallel), 186. 1871.
Plants 30–60(–110) cm. Stems (often relatively numerous, clustered in clonal patches) simple. Leaves 5–7 pairs, mostly cauline (basal leaves usually withered by flowering); sessile or subsessile (proximalmost with connate-sheathing bases); blades lanceolate to lance-elliptic, 5–12(–15) × 1.5–3.5 cm, margins usually entire, rarely denticulate, apices acute to acuminate, faces scabrid-puberulent, sometimes glandular (distal leaves not much reduced). Heads 3–20(–35). Involucres turbinate-campanulate. Phyllaries 11–15(–20), narrow to broadly lanceolate. Ray florets 6–15; corollas yellow. Disc florets 6–11; corollas yellow; anthers yellow. Cypselae brown to black, 3–7 mm, glabrous or sparsely hirsutulous, stipitate-glandular; pappi stramineous to tawny, bristles barbellate to subplumose. 2n = 57, 76.
Phenology: Flowering Jun–Oct.
Habitat: Montane coniferous forests to alpine, usually moist areas, stream banks or late snow-melt areas
Elevation: 1300–3700 m
Distribution
Alta., B.C., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.
Discussion
Selected References
None.