Chamissonis: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species. 

	stem leaves numerous, in 4-8 pairs; NOT [stem leaves less numerous, in 1-3 pairs] (BF)
	cauline leaves mostly 5-10 pairs; NOT [cauline leaves mostly 2-4 pairs, not including those (in any) of the basal cluster] (FOA)
	leaves oblong-lanceolate to linear; NOT [leaves cordate to oblong]
	lower stem leaves lanceolate; NOT [lower stem leaves ovate or deltoid]
	lower stem leaves entire to remotely dentate; NOT [lower stem leaves sharply dentate]
	heads several to many; NOT [heads solitary or few]
	involucral bracts obtuse or merely acutish; NOT [involucral bracts definitely acute]
	involucral bracts bearing a tuft of long hairs at or just within the tip; NOT [tips of involucral bracts not markedly more hairy than the body]
	pappus straw-coloured or brownish; NOT [pappus often white]
	pappus barbellate; NOT [pappus often subplumose]

Arnica: Answers to key questions in Budd's Flora  and Flora of Alberta leading to this genus. 

	juice watery; NOT [juice milky]
	leaves opposite; NOT [leaves alternate or basal]
	involucral bracts usually one series, not or scarcely imbricated; NOT [involucral bracts in 2 or more series, well imbricated] (BF)
	receptacle naked (FOA)
	flower heads with florets both tubular and ray
	ligulate flowers when present pistillate or neuter; NOT [flowers all perfect]
	ray florets yellow; NOT [rays white, to pink, purple or blue]
	stamens united to form a tube around the pistil
	pappus composed of hairs; NOT [pappus chaffy, or of firm awns, or of bristles, or of scales, or a crown or none]