Cardamine microphylla J. Adams, Mém. Soc. Imp. Naturalistes Moscou 5: 111. 1817, non J. Presl and C. Presl, Delic. Prag. 15. 1822, nec (Willdenow) O. E. Schulz, Bot. Jahrb. Syst. 32: 342. 1903. TYPE:
Cardamine minuta Willdenow ex O. E. Schulz
Herbs, perennial, glabrous or rarely sparsely hirtellous on leaves. Rhizomes slender, cylindrical, 0.7–1.5 mm in diam.; stolons absent. Stems 0.3–1.5(–2) dm, erect or ascending, simple, glabrous. Rhizomal leaves pinnately 5–7-foliolate, not fleshy, (1.3–)2.5–6.5 cm; petiole (0.5–)1.5–5.5 cm; terminal leaflet ovate to elliptic, (2–)4–12(–15) × (1–)2.5–6 mm, glabrous or rarely pubescent, base cuneate to obtuse, margin entire, apex apiculate, petiolule 1.5–7 mm; lateral leaflets about as large as or smaller than terminal leaflet, similar in other aspects; cauline leaves 1–3, 5–7-foliotate, alternate; petiole 2–15 mm, base not auriculate; terminal leaflet ovate to elliptic, 4–13 × 1–7 mm, subsessile or with a petiolule to 2 mm, base cuneate, margin entire, apex apicualte; lateral leaflets similar to terminal one. Racemes ebracteate; fruiting pedicels erect to ascending, 0.7–1.5(–2.5) cm. Sepals ovate to oblong, 3–4 × 1.8–2.5 mm, erect, base of lateral pair slightly saccate; petals white or rarely lavender, broadly obovate, 7–10 × 3–6 mm, clawed, apex rounded; median filament pairs 3–4.5 mm, lateral pair 2–3 mm; anthers oblong, 1–1.5 mm. Fruit linear, 2–3 cm × 1.2–1.7 mm; valves glabrous; style 1–2 mm; ovules and seeds 12–16 per fruit. Seeds brown, oblong, ca. 1.5 × 1 mm. 2n = 28, 42, 64.
Flowering: Jul–Aug.
Habitat: streamsides, sand and cobbles on gravel bars, shale banks, floodplains, alluvial sand between cobbles, moist moss, turf, seepage areas, meadows, wet grounds.
Elevation: 0–1600 m.
Distribution: Canada (NW Northwestern Territories, N Yukon), Russia (Far East, Siberia), United States (NE Alaska).