Arabis furcata |
Brassicaceae tribe Arabideae |
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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. | Annuals, biennials, or perennials [subshrubs]; eglandular. |
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). |
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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. |
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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. |
petiolate or sessile; blade base auriculate or not, margins entire or dentate. |
Trichomes | stalked or sessile, usually stellate, dendritic, cruciform, or forked, sometimes mixed with simple ones, rarely malpighiaceous. |
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Racemes | simple, (dense or lax). |
usually ebracteate, often elongated in fruit. |
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. |
actinomorphic; sepals erect, ascending, or spreading, lateral pair seldom saccate basally; petals white, yellow, orange, pink, or purple, claw usually present, usually distinct; filaments unappendaged, not winged; pollen 3-colpate. |
Fruiting pedicels | suberect, ascending, or divaricate, (2–)4–17(–22) mm, (glabrous). |
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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). |
silicles or siliques, usually dehiscent, very rarely indehiscent, unsegmented, latiseptate or terete; ovules 2–70(–88)[–110+] per ovary; style usually distinct, sometimes obsolete; stigma usually entire, rarely 2-lobed. |
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. |
biseriate or uniseriate [rarely aseriate]; cotyledons accumbent. |
Arabis furcata |
Brassicaceae tribe Arabideae |
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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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North America; Mexico; South America; Europe; Asia; n Africa |
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.) |
Genera 8, species ca. 460 (4 genera, 139 species in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 262. | FNA vol. 7, p. 256. |
Parent taxa | Brassicaceae > tribe Arabideae > Arabis | Brassicaceae |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | A. suksdorfii | |
Name authority | S. Watson: Proc. Amer. Acad. Arts 17: 362. (1882) | de Candolle: Mém. Mus. Hist. Nat. 7: 229. (1821) |
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