Arabis furcata |
Arabis eschscholtziana |
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Cascade rock-cress, Columbia Gorge rockcress, fork-hair rock-cress |
Eschscholtz's hairy rock-cress, Eschscholtz's rockcress, hairy rockcress, Pacific coast rockcress |
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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. | Biennials or perennials; (caudex branched); usually densely hirsute (at least basally), trichomes simple or stalked, forked, sometimes glabrescent with mostly simple 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). |
simple or several from base (rosette), erect, often branched distally, 2–7(–10) dm, (hirsute basally, trichomes simple and minutely stalked, forked, rarely almost exclusively glabrous). |
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. |
petiole 0.7–3 cm, (ciliate or not); blade broadly spatulate to narrowly oblanceolate, 1.2–10 cm × 7–30 mm, margins entire or dentate, apex obtuse or acute, surfaces usually pubescent, sometimes glabrous, trichomes simple, forked and stalked, stellate. |
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. |
(2–)4–12(–18), (well-spaced or, rarely, overlapping); blade ovate to oblong or lanceolate, 1.5–6.5(–10) cm × 5–30 mm, base auriculate, margins dentate or entire, apex acute or obtuse, surfaces sparsely hirsute or glabrous. |
Racemes | simple, (dense or lax). |
simple or branched. |
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. |
sepals oblong, 3.5–5 × 1.2–2 mm, lateral pair saccate basally; petals white, rarely pink, linear-oblanceolate or narrowly spatulate, (5.5–) 6.5–9(–10) × 1.5–3 mm, apex obtuse; filaments 3.5–6 mm; anthers oblong, 0.7–1 mm. |
Fruiting pedicels | suberect, ascending, or divaricate, (2–)4–17(–22) mm, (glabrous). |
erect to erect-ascending, 3.5–10(–15) mm, (glabrous or sparsely pubescent). |
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). |
erect to erect-ascending, (often appressed to rachis), torulose, 3.5–6.5 cm × 1.2–1.8(–2) mm; valves each with prominent midvein extending full length or to middle; ovules 54–80 per ovary; style (0.1–)0.3–1 mm. |
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. |
usually narrowly winged throughout or only distally, rarely not winged, oblong or suborbicular, 1–1.8 × 0.9–1.3 mm; wing to 0.2 mm wide distally. |
2n | = 32, 64. |
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Arabis furcata |
Arabis eschscholtziana |
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Phenology | Flowering May–Jul(-Aug). | Flowering (Apr-)May–Jul. |
Habitat | Open slopes, alpine meadows, cliffs, ridge crests | Rocky slopes, crevices, and ledges, meadows, moist banks and grounds, granitic soil, wooded slopes |
Elevation | (50-)1000-2100 m ((200-)3300-6900 ft) | 0-2800 m (0-9200 ft) |
Distribution |
OR; WA
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AK; CA; ID; MT; NV; OR; UT; WA; WY; AB; BC; YT
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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.) |
G. A. Mulligan (1996) recognized Arabis eschscholtziana as a distinct species; R. C. Rollins (1941, 1993) treated it as a variety of A. hirsuta. As discussed under A. pycnocarpa, A. hirsuta does not occur in North America, and the characters separating all three species (see key to species), as well as the different ploidy levels, support Mulligan’s conclusion. Both M. Hopkins (1937) and R. C. Rollins (1941, 1993) recognized the glabrous or subglabrate forms native to North America as a distinct variety, var. glabrata; G. A. Mulligan (1996) did not accord such forms any taxonomic status. Glabrous and subglabrate forms occur in both Arabis eschscholtziana and A. pycnocarpa and sometimes even within a population that has moderately to densely pubescent forms. I support Mulligan’s view in not recognizing the glabrous forms as an infraspecific taxon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 262. | FNA vol. 7, p. 261. |
Parent taxa | Brassicaceae > tribe Arabideae > Arabis | Brassicaceae > tribe Arabideae > Arabis |
Sibling taxa | ||
Synonyms | A. suksdorfii | A. hirsuta subsp. eschscholtziana, A. hirsuta var. eschscholtziana, A. hirsuta var. glabrata, A. ovata var. glabrata, A. pycnocarpa var. glabrata, A. rupestris, A. stelleri var. eschscholtziana, Turritis spathulata |
Name authority | S. Watson: Proc. Amer. Acad. Arts 17: 362. (1882) | Andrzejowski: in C. F. von Ledebour, Fl. Altaica 3: 25. (1831) |
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