Cardamine occidentalis (S. Watson ex B. L. Robinson) Howell, Fl. Northw. Amer. 50. 1897, combination was also made by O. E. Schulz, Bot. Jahrb. Syst. 32: 539. 1903; C. pratensis Linnaeus var. occidentalis S. Watson ex B. L. Robinson in A. Gray, Syn. Fl. N. Amer. 1: 158. 1895. TYPE: United States,

Cardamine neglecta Greene, Pittonia 3: 154. 1897. TYPE: United States,

Herbs, perennial, glabrous or hirsute. Rhizomes fleshy, ovoid or globose, at base of stem, 3–10 mm in diam; stolons absent. Stems 1–5 dm, erect to ascending, 1 from base, simple or branched above, not flexuous, glabrous or pubescent proximally. Basal leaves not rosulate, pinnately compound, (3 or)5(or 7)-foliolate, 2–10 cm, glabrous; petiole 0.5–6.5 cm; terminal leaflet orbicular to broadly ovate or subcordate, 0.5–2 × 0.7–2.5 cm, margin entire or repand, base cordate to rounded, petioule 0.3–1.8 mm; lateral leaflets smaller than terminal, ovate, entire, petiolulate or subsessile; cauline leaves 3–7, middle ones 5–7-foliolate, gradually reduced in size and becoming 3-folioate upwards; petiole 0.5–3 cm, base not auriculate; terminal leaflet obovate to oblanceolate, 0.5–2.6 × 0.3–1.3 cm, shallowly toothed or entire to repand, lateral leaflets smaller. Racemes ebracteate; fruiting pedicels divaricate-ascending, 0.7–1.8 cm. Sepals oblong, 1.7–2 × 1–1.2 mm, base of lateral pair not saccate; petals white, oblanceolate, 4–6 × 1.5–2 mm, not clawed; median filament pairs 2–2.5 mm, lateral filaments 1–1.5 mm; anthers ovate, 0.3–0.5 mm. Fruit linear, 1.5–3.3 cm × 1.7–2.2 mm; valves glabrous or sparsely pubescent, torulose; style 0.5–1.5 mm; ovules and seeds 18–40 per fruit. Seeds brown, ovate, 1–1.6 × 1–1.2 mm, wingless. 2n = 64.

Flowering: Apr–Jul.

Habitat: muddy grounds, lake margins, shallow streams and creeks, meadows.

Elevation: 150–1500 m.

Distribution: Canada (British Columbia), United States (Alaska, N California, Oregon, Washington).