Arvensis: Answers to key questions in Budd's Flora and Vascular Flora of Alberta: An Illustrated Guide leading to this species. 

	middle and upper leaves (at least) merely toothed; NOT [most leaves deeply pinnately lobed]
	pods approximately 2 mm thick; NOT [pods approximately 4 mm thick]
	pods usually glabrous; NOT [pods densely pubescent]
	beak of pod approximately half as long as the body; NOT [beak usually longer than the body]

Sinapis: Answers to key questions in Budd's Flora and Vascular Flora of Alberta: An Illustrated Guide leading to this genus. 

	plants of dry habitats; NOT [plants of wet habitats]
	hairs, when present, simple; NOT [hairs attached at the middle, sessile, appressed, malpighian or stellate]
	plants without stalked glands; NOT [plants with many-celled, stalked glands]
	prominent cauline leaves present; NOT [leaves mostly basal or lower cauline]
	cauline leaves usually short petiolate (at least distally); NOT [cauline leaves more or less clasping, auriculate or sagittate at base]
	cauline leaves simple (sometimes deeply cut, but the blade continuous between lobes); NOT [stem leaves divided into leaflets]
	raceme mostly without bracts; NOT [raceme with small leafy bracts at the base of most flowers]
	flowers smaller than 30-40 mm across
	sepals spreading to reflexed; NOT [sepals usually erect or ascending, rarely spreading]
	petals present; NOT [petals absent]
	petals yellow
	petals with veins of the same color intensity as the rest of the blade; NOT [petals with dark, purple or brown veins]
	pods usually at least 4 times as long as wide; NOT [pods usually not more than 3 times as long as wide]
	pods not compressed at right angles to the central partition; NOT [pods compressed at right angles to the central partition]
	pods circular in cross section; NOT [pods flattened]
	pods with 3-7 prominent veins per side; NOT [pods with 1 prominent vein per side]
	pods with a long, distinct beak; NOT [pods scarcely beaked ]
	beak conspicuously flattened; NOT [beak more or less rounded]
	beak often containing a seed; NOT [beak seedless]
	pods opening lengthwise via separation of two valves, not breaking up cross ways along constrictions between seeds
	seeds in a single row; NOT [seeds more or less in 2 rows]
	seeds plump; NOT [seeds flat]

Cruciferae: Answers to key questions in Budd's Flora  leading to this family. 

	herbs; NOT [shrubs or trees]
	plants terrestrial or semiaquatic; NOT [plants aquatic, leaves submerged or floating]
	plants not with colored milky juice
	plants with more than one normal leaf
	some or all leaves alternate; NOT [leaves opposite, whorled, or basal]
	leaves without stipules, or having glands; NOT [leaves with stipules]
	flowers with two floral rings
	calyx regular; NOT [calyx irregular, some sepals smaller than others]
	sepals 4
	corolla regular in shape; NOT [corolla irregular in shape]
	each petal distinct from the others
	petals 4
	stamens 6, four long and two short
	ovary superior; NOT [ovary inferior]
	carpels 1 or 2