Answers to key questions in Vascular Flora of Alberta: An Illustrated Guide leading to this genus (and species). 

	juice usually watery; NOT [juice milky]
	lowest leaves not triangular-egg-shaped to kidney shaped, not white-woolly beneath
	flower heads small to large, 1-few (rarely many) in round- to flat-topped clusters; NOT [flower heads usually small and numerous, in elongated clusters]
	involucres neither nut/bur-like nor with hooked prickles (sometimes with straight spines); NOT [involucres with short, hooked prickles, or nut/bur-like and spiny]
	receptacles hemispheric to cone-shaped; NOT [receptacles flat or +/- convex]
	involucral bracts in >= 2 rows, not enfolding the achenes; NOT [involucral bracts in 1 row, equal, each enfolding an achene]
	involucres usually with  >6 bracts; NOT [involucres with about 4-5 bracts]
	receptacles naked or with 1 row of  papery scales between the ray and disc florets; NOT [receptacles covered with bristles or scales (a few central florets sometimes bractless)]
	flower heads discoid, with disc florets only.
	pappus a minute crown or absent; NOT [pappus of short, distinct bristles or scales], NOT [pappus of hair-like or feathery bristles (at least in part)]