Annuals or perennials; (short-lived); glabrous throughout. Rhizomes cylindrical, slender, 0.5-1.5 mm diam. Stems (simple from base), erect, (not flexuous), unbranched or branched basally, 0.6-3 dm. Basal leaves rosulate or not, 3 or 5-foliolate, 1-6 cm, leaflets petiolulate; petiole 0.4-2.5 cm; lateral leaflets similar to terminal, considerably smaller; terminal leaflet (petiolule 0.1-0.4 cm), blade obovate to orbicular or subcordate, 0.3-1.5(-2.0) cm × 2.5-16(-18) mm, base obtuse to rounded or cordate, margins entire or dentate to slightly sinuately lobed. Cauline leaves 2-4, 3 or 5-foliolate, blade similar to basal, gradually reduced in size as bract, distalmost ones subtending pedicels of flowers (usually simple); leaflet blade or bract linear to linear-oblanceolate, 0.2-0.8 cm. Racemes bracteate throughout. Fruiting pedicels divaricate-ascending, (10-)15-30(-45) mm. Flowers: sepals oblong, (2-)3 × 0.7(-1) mm, lateral pair not saccate basally; petals purple or pink, obovate, 6-9 × 3-4 mm, (not clawed); filaments: median pairs 3-3.5 mm, lateral pair 2-2.5 mm; anthers oblong, 0.7-1 mm. Fruits linear, (torulose), 2-3 cm × 1-1.5 mm; ovules 14-20 per ovary; style 2-4 mm. Seeds brown, oblong to ovoid, 1.7-2.2 × 1-1.5 mm, (winged distally).

Flowering May-Jun. Moist mossy cliffs, rocky slopes, mossy banks; of conservation concern; 800-900 m; Oreg.

Cardamine pattersonii is known from Saddle Mountain and Onion Peak in Clastop County.