Monographs Details: Arnica
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Genus Description - Heads radiate (in our spp.) or sometimes discoid, the rays pistillate, yellow or orange, relatively few and large; invol bracts herbaceous, subequal but ± evidently biseriate; receptacle convex, naked; disk-fls perfect and fertile, yellow; style-branches flattened, truncate, penicillate; achenes cylindric, 5–10-nerved; pappus of numerous white to tawny, barbellate to subplumose, capillary bristles; perennial herbs with opposite lvs (uppermost lvs rarely alternate) and solitary to numerous, rather large, turbinate to hemispheric heads. 27, temperate and boreal parts of N. Hemisphere.