Holboellii:  Answers to key questions in Budd's Flora (BF) and Flora of Alberta (FOA) leading to this species.   plants mostly well over 3 dm tall; NOT [plants mostly under 2 dm tall] pubescence of the lower stem often stellate to dendritic; NOT [pubescence (if any) of the lower stem simple to bifurcate, often appressed] hairs more freely branched; NOT [hairs of the lower stems and leaves predominantly trifurcate] basal leaves mostly with trifurcate to stellate or dendritic hairs; NOT [basal leaves with malpighiaceous hairs] pubescence of basal leaves felty pods always sharply reflexed and pendulous; NOT [pods in part spreading, in part descending], NOT [pods spreading, never reflexed or pendulous], NOT [pods erect or  ascending, often tightly appressed] siliques 1.5-2.5 mm broad; NOT [siliques less than 1.5 mm broad], NOT [siliques 2-3 mm broad] seeds mostly uniseriate; NOT [seeds biseriate] wing of seed between 0.3 and 0.5 mm wide; NOT [seeds wingless or the wing less than 0.3 mm wide], NOT [wing of seed nearly 1 mm wide]

 

Arabis: Answers to key questions in Budd's Flora and Flora of Alberta leading to this genus.   The answers do not necessarily apply to all members of Arabis found on the Canadian prairies, but they all do apply to A. holboellii. plants generally NOT glaucous plants pubescent; NOT [plants glabrous] plants with pubescence mostly or entirely of branched hairs; NOT [plants with pubescence of simple hairs] leaves more or less entire; NOT [leaves deeply serrate to pinnate] cauline leaves auriculate, clasping flowers much smaller than 20-25 mm across petals white, pink-tinged, pink or purple; NOT [petals yellow] pods usually at least 4 times as long as wide; NOT [pods usually not more than 3 times as long as wide] pods strongly flattened; NOT [pods round in cross section] pods NOT compressed at right angles to the central partition pods scarcely beaked; NOT [pods with a long, distinct beak] central partition entire; NOT [central partition with an opening sometimes almost reduced to the margin]

 

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, and with each petal distinct from the others calyx regular; NOT [calyx irregular, some sepals smaller than others] sepals 4 corolla regular in shape petals 4; NOT 5 stamens usually 6, four long and two short; NOT [stamens 6, of equal length], NOT [stamens usually more than 10] ovary superior; NOT inferior carpels 1 or 2; NOT [carpels 3-5]