Cardamine holmgrenii

Perennials; glabrous throughout. Rhizomes slender, 0.5-1 mm diam. Stems erect to ascending, branched, 1.5-2 dm. Rhizomal and basal leaves absent. Cauline leaves 3 or 4, 3- or 5-foliolate, petiolate, leaflets petiolulate; petiole 0.5-1.7 cm, base not auriculate; lateral leaflet blade linear to linear-lanceolate, 0.9-1.5 cm × 1-3 mm, margins entire; terminal leaflet (petiolule 0.3-0.5 cm), blade obovate to lanceolate (linear distally), 1.3-2.3 cm × 2-8 mm, base cuneate, margins entire or subapically 1- or 2-toothed. Racemes ebracteate. Fruiting pedicels ascending to suberect, 5-14 mm. Flowers: sepals oblong, 1.2-1.5 × 0.6-0.8 mm, lateral pair not saccate basally; petals white, oblanceolate, 2-2.5 × 0.8-1 mm, (not clawed, apex rounded); filaments: median pairs 1.5-1.8 mm, lateral pair 1-1.2 mm; anthers ovate, 0.2-0.3 mm. Fruits linear, 1-2 cm × ca. 1 mm; ovules 16-24 per ovary; style 0.5-0.7 mm. Seeds brown, oblong, 1.2-1.5 × 0.8-1 mm.

Flowering Jul-Aug. Boggy slopes; Oreg.

Cardamine holmgrenii is known only from the type collection, from the Blue Mountains in Baker County.