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

	plants generally taller; NOT [plants mostly 0.5-2.0 (3.0) dm tall]
	stems rigid
	stems gray puberulent; NOT [stem glabrous]
	leaves firm
	leaves very rough
	leaves gray pubescent; NOT [leaves glabrous]
	petiole of the basal leaves NOT conspicuously ciliate
	inflorescence corymbose, with the branches slanting upward, forming a rounded or flat-topped inflorescence; NOT [inflorescence a panicle or spike], NOT [inflorescence usually racemose, the inflorescence cylindrical to narrowly oval, or paniculate, with spreading or arching branches, the heads often secund]
	involucral bracts striate
	ray florets usually less than 5 mm long; NOT [ray florets large, 5-8 mm long]
	ray florets yellow

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

	plants with fibrous roots; NOT [plants with a taproot]
	juice watery; NOT [juice milky]
	leaves alternate or basal; NOT [leaves opposite]
	leaves simple, not pinnatifid or divided
	leaves never spinescent
	heads small and numerous, in terminal or axillary clusters; NOT [heads usually solitary at ends of branches]
	involucral bracts in 2 or more series, well-imbricated; NOT [involucral bracts usually one series, not or scarcely imbricated (overlapping like shingles)] (BF)
	involucral bracts either imbricate in several series, or broad and somewhat leafy, or both; NOT [involucral bracts uniseriate, equal, narrow, commonly with a few much shorter outer ones at the base] (FOA)
	receptacle naked
	flower heads with florets both tubular and ray (radiate heads)
	ligulate flowers pistillate or neuter; NOT [ligulate flowers perfect]
	ray florets yellow
	stamens united to form a tube around the pistil
	pappus wholly or partly of capillary bristles, sometimes plumose; NOT [pappus chaffy or of firm awns, scales, or a crown or none]
	pappus single, bristles sometimes unequal but not distinctly divided into an inner and outer series of two lengths; NOT [pappus double, bristles of the outer series inconspicuous, distinctly shorter than the inner]