Cardamine flexuosa Withering subsp. pensylvanica (Muhlenberg ex Willdenow) O. E. Schulz; C. hirsuta Linnaeus var. pensylvanica (Muhlenberg ex Willdenow) P. W. Graff; C. multifolia Rydberg; C. pensylvanica var. brittoniana Farwell; C. rotundifolia Michaux var. diversifolia O. E. Schulz; Dracamine pensylvanica (Muhlenberg ex Willdenow) Nieuwland

Annuals or biennials; sparsely hirsute basally, glabrous distally. Rhizomes absent. Stems (simple from base), erect, (not flexuous), unbranched or branched distally, (0.5-)1.5-5.5(-7) dm. Basal leaves (soon withered), not rosulate, similar to proximalmost cauline leaves, 4-15 cm. Cauline leaves (3-)5-20(-35), pinnately (5 or) 7-13(-19)-foliolate, sometimes appearing pinnatisect, lobe number similar to leaflets (middle and proximal ones 2-11 cm), petiolate, leaflets petiolulate, subsessile, or sessile; petiole (0.4-)1-3.5(-4.5) cm, base not auriculate, (often sparsely hirsute); lateral leaflets shortly petiolulate or sessile, (decurrent on rachis smaller than terminal, distalmost blades narrower, with fewer lobes or leaflets), margins entire or crenate; terminal leaflet (subsessile or petiolule to 1 cm), blade suborbicular, obovate to oblanceolate, or elliptic, 1.3-3(-4) cm × 6-25 mm, base often cuneate, margins entire, repand, or obscurely 3 or 5-lobed. Racemes ebracteate. Fruiting pedicels divaricate-ascending, (3-)4-10(-13) mm. Flowers: sepals oblong, (1-)1.3-2.3 × 0.5-1 mm, lateral pair not saccate basally; petals white, narrowly spatulate to oblanceolate, 2-3.5(-4) × 0.8-1.5 mm, (not clawed); filaments: median pairs 1.5-2.5 mm, lateral pair 1-2 mm; anthers ovate, 0.2-0.3 mm. Fruits linear, (torulose), (1.4-)1.7-2.7(-3.2) cm × 0.8-1.1 mm; ovules 40-80 per ovary; style 0.5-1 mm. Seeds brown, oblong to ovoid, 0.7-1.1 × 0.5-0.8 mm. 2n = 32, 64.

Flowering Apr-Jul. Marshes, streams, swamps, ditches, seepage, springs, lake margins, mesic bottomland and upland forests, wet areas, ledges of sheltered bluffs, banks and shallow water of streams and spring branches, margins of crop fields, waste ground; 0-2800 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.

We have not seen material of Cardamine pensylvanica from Nebraska or South Dakota; it is very likely that the species grows in these states as well.