Draba is a large and complex genus, mostly of alpine, boreal and arctic regions, represented by only a few relatively distinctive species in our area. The siliques are strongly flattened and in many species are ± twisted.
1. Petals deeply bilobed; stems leafless, all leaves in a basal rosette.
1. Petals entire or slightly notched at apex; plants with at least some cauline leaves near the base of the stem.
2. Plant a delicate slender-stemmed annual (or winter-annual); fruit narrowly elliptic or oblong, tapering no more toward the apex than the base and no broader below the middle than at it; axis of the inflorescence glabrous.
3. Petals pale yellow, less than 2.2 mm long; cauline leaves scattered nearly to the open, elongate raceme.
3. Petals white, ca. 3–4 mm long (or absent); cauline leaves near the base (sometimes scarcely distinguishable from the basal rosette), remote from the crowded inflorescence.
2. Plant a ± strong perennial (or sturdy biennial); fruit mostly slightly broader below the middle, tapering more toward the apex than the base; axis of inflorescence usually sparsely to densely pubescent.
4. Stem very leafy (at least 20 cauline leaves between basal rosette and lowest pedicel); axis of inflorescence densely pubescent; fruit not twisted.
4. Stem with few cauline leaves but many basal leaves (often with short leafy basal shoots); axis of inflorescence sparsely pubescent or glabrate.
5. Fruit ± densely stellate pubescent.
5. Fruit glabrous or sparsely pubescent when young.
6. Style 0.25–0.5 mm long, clearly longer than broad; fruit usually spirally twisted ca. 1/4 to a full turn.
6. Style ca. 0.2 mm long, about as wide as long; fruit flat, not spirally twisted.