Cardamine pratensis Linnaeus var. angustifolia Hooker

Perennials; (cespitose); glabrous. Rhizomes absent. Stems erect, unbranched or, rarely, branched, 0.5-1.6(-3.5) dm. Basal leaves (7 or) 9-21-foliolate, (thick, veins impressed); leaflets petiolulate or sessile; lateral lobes or leaflets similar to terminal; terminal lobe or leaflet blade orbicular, broadly ovate to lanceolate, base rounded to cuneate, margins usually entire. Cauline leaves 2-4(-7), pinnatisect or pinnately compound, (7 or) 9-21-foliolate, (thick, veins impressed), petiolate, leaflets petiolulate or sessile; petiole base not auriculate; lobes or leaflets (of proximal leaves) (4-)7-10 each side of rachis, fewer distally, distal leaves with 4 or 5 lobes or leaflets each side of rachis; terminal leaflet petiolulate or sessile, blade (or lobe) narrowly lanceolate to lanceolate, base cuneate, margins entire. Racemes ebracteate. Fruiting pedicels erect-ascending, 5-15 mm. Flowers: sepals oblong or ovate, 3.6-4.4 mm, lateral pair saccate basally, (green with hyaline margins); petals white-lilac, 9-12.3 × 4.8-6.8 mm, (clawed, apex rounded or emarginate); filaments: median pairs 3.5-4.5 mm, lateral pair 2-3 mm; anthers narrowly oblong, 0.9-1.4 mm. Fruits linear, 1-1.8 cm × ca. 1.5 mm; ovules ca. 16 per ovary; style ca. 1 mm, (stout). Seeds brown, oblong, ca. 1.5 mm. 2n = 56, 60, 64, 80-100.

Flowering Jun-Aug. Wet meadows, marshes, margins of ponds, along streams, seacoasts, swamps; Greenland; Man., Nfld. and Labr., N.W.T., Nunavut, Que., Yukon; Alaska; n Eurasia.