Proc. Amer. Acad. Arts 17: 362. 1882.
Perennials; (caudex simple or branched, covered with persistent petiolar remains); glabrous or sparsely pubescent, trichomes simple or short-stalked, forked (0.3–1 mm), these rarely mixed with fewer, unequal 3-rayed ones. Stems simple or few from base (caudex), erect, usually unbranched, rarely branched (few) distally, (0.7–)1–3.8(–4.5) dm, (glabrous throughout or sparsely pubescent basally to distally). Basal leaves: petiole (0.4–)1–3(–4.5) cm, (glabrous or sparsely ciliate); blades oblanceolate, spatulate, or obovate, (0.7–)1.2–3 cm × 5–17(–22) mm, margins entire or dentate, (often ciliate), apex obtuse, surfaces glabrous or sparsely pubescent, trichomes short-stalked, forked and simple. Cauline leaves (2 or) 3–5 (or 6); blade linear, oblong, obovate, or oblanceolate, 0.7–3(–4) cm × 3–8 mm, base cuneate, not auriculate, margins usually entire, rarely few-toothed, apex obtuse, surfaces usually glabrous, rarely margins ciliate. Racemes simple, (dense or lax). Fruiting pedicels suberect, ascending, or divaricate, (2–)4–17(–22) mm, (glabrous). Flowers: sepals (greenish), oblong, 3–4 × 1.5–2 mm, (usually glabrous, rarely with few trichomes subapically), lateral pair saccate basally; petals white, spatulate, 7–11 × 2.5–4 mm, apex rounded; filaments 3.5–5 mm; anthers oblong, 0.8–1 mm. Fruits ascending to suberect, (not appressed to rachis), slightly torulose, sometimes slightly curved, strongly flattened, (2–)2.5–4(–4.6) cm × 1.7–2.2 mm; valves each with prominent midvein extending full length; ovules 14–26 per ovary; style 0.5–1.2(–1.6) mm, (slender). Seeds winged distally, oblong to broadly ovate, (1.5–)1.8–2.5(–3) × 1–1.3 mm; wing (0.2–)0.4–0.8(–1) mm wide.
Phenology: Flowering May–Jul(-Aug).
Habitat: Open slopes, alpine meadows, cliffs, ridge crests
Elevation: (50-)1000-2100 m
Arabis furcata is known in Washington from Chelan, Kittitas, Klickitat, Okanogan, Skamania, and Yakima counties, and in Oregon from Clackamas, Hood River, Multnomah, and Wasco counties.