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

	plants of lowland habitats; NOT [plants of alpine habitats]
	plants mostly terrestrial; NOT [plants aquatic, usually submerged]
	plants glabrous; NOT [plants not glabrous, puberulent to pubescent]
	plants with leafy stems; NOT [plants with basal leaves only]
	cauline leaves often clasping
	cauline leaves often auriculate
	petals white; NOT [petals yellow]
	fruit 8-18 mm long; NOT [fruit shorter]
	fruit 2-3 times longer than broad or shorter; NOT [fruit much longer than broad]
	fruit orbicular; NOT [fruit ovate to orbicular], NOT [fruit triangular]
	fruit not strongly inflated
	fruit strongly flattened
	fruit flattened at right angles to septum (central partition); NOT [fruit flattened parallel to septum, if at all]
	fruit broadly winged all round; NOT [fruit wingless or only narrowly winged towards the apex]
	more than one seed in each compartment of pod; NOT [one seed in each compartment of pod]

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

	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; NOT [petals 5]
	stamens 6, four long and two short
	ovary superior; NOT [ovary inferior]
	carpels 1 or 2; NOT [carpels 3-5]