Arabis furcata |
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Cascade rock-cress, Columbia Gorge rockcress, fork-hair rock-cress |
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Habit | 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). |
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. |
Fruiting pedicels | suberect, ascending, or divaricate, (2–)4–17(–22) mm, (glabrous). |
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. |
Arabis furcata |
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Phenology | Flowering May–Jul(-Aug). |
Habitat | Open slopes, alpine meadows, cliffs, ridge crests |
Elevation | (50-)1000-2100 m ((200-)3300-6900 ft) |
Distribution |
OR; WA
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Discussion | 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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 262. |
Parent taxa | |
Sibling taxa | |
Synonyms | A. suksdorfii |
Name authority | S. Watson: Proc. Amer. Acad. Arts 17: 362. (1882) |
Web links |