8. Arabis furcata S. Watson, Proc. Amer. Acad. Arts. 17: 362. 1882.
Arabis suksdorfii Howell
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.
Flowering May-Jul(-Aug). Open slopes, alpine meadows, cliffs, ridge crests; (50-)1000-2100 m; Oreg., Wash.
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.