Arabis caucasica |
Arabis oregana |
|
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garden rockcress, mountain rockcress, rock cress |
Oregon rock-cress |
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Habit | Perennials; (stoloniferous, with vegetative rosettes, loosely cespitose to somewhat pulvinate); sparsely to moderately pubescent, trichomes stalked, cruciform, stellate, mixed with simple and forked-stalked ones. | Perennials; (caudex simple or branched, with some persistent petiolar remains); sparsely to moderately pubescent, trichomes bulbous-based, simple and long-stalked, forked, (to 2 mm), these often mixed with fewer 3-rayed, stalked stellate ones. |
Stems | several to many from base, erect, ascending to decumbent, branched (several), 1.5–3.5(–5) dm. |
simple or few from base (caudex), erect, unbranched distally, (0.6–)1.7–4.5(–5) dm, (usually pubescent throughout, rarely subglabrate, coarsely hirsute, trichomes simple, mixed with forked ones). |
Basal leaves | petiole 0–1 cm; blade spatulate, oblanceolate, oblong, or obovate, 2–5.5(–8) cm × 9–18(–25) mm, margins dentate to denticulate, apex obtuse or acute, surfaces usually pubescent, rarely subglabrate, trichomes stellate with some rays branched. |
petiole 0.5–2(–3) cm, (ciliate); blade oblanceolate to obovate, (1–)2–5(–9) cm × (5–)8–18(–22) mm, margins entire or repand to dentate, (ciliate), apex obtuse, surfaces pubescent or glabrous, trichomes simple and forked, sometimes mixed with 3-rayed stellate ones. |
Cauline leaves | 4–8; blade oblong or ovate, 1–5 cm × 5–20 mm, base subcordate or auriculate, margins usually dentate, rarely subentire, apex acute or obtuse. |
3–6 (or 7); blade oblong, 1–3(–6) cm × 2–7(–15) mm, base not auriculate, margins entire or dentate, (ciliate or not), apex obtuse, surfaces pubescent as basal leaves or glabrous. |
Racemes | simple, (lax). |
simple, (dense). |
Flowers | sepals oblong, 4.5–8 × 1–2 mm, lateral pair conspicuously saccate basally; petals white, spatulate to obovate, 10–19 × 4–8 mm, apex obtuse; filaments 4–7 mm; anthers oblong, 0.7–1.2 mm. |
sepals (purple), oblong, (5–)6–8 × 1.5–2 mm, lateral pair saccate basally; petals purple or pink, spatulate, (10–)12–15(–16) × (3–)4–5 mm, apex obtuse; filaments (4–)5–8 mm; anthers narrowly oblong, 1.2–1.8 mm. |
Fruiting pedicels | ascending to divaricate, 7–17(–20) mm. |
ascending to erect, 5–10 mm, (pubescent or glabrous). |
Fruits | ascending to spreading, torulose, (3–)4–7 cm × 1–2 mm; valves each with midvein absent or obscure, along proximal 1/2; ovules 40–60 per ovary; style 0.5–1 mm. |
erect or nearly so, slightly torulose, (3–)4.5–6 cm × 1.5–2 mm; valves each with prominent midvein; ovules 24–30 per ovary; style 0.5–1 mm. |
Seeds | narrowly winged throughout, ovate, 1–1.4 × 0.9–1.1 mm; wing 0.1–0.2 mm wide. |
narrowly winged distally or not winged, oblong, 1.8–2.2 × ca. 1 mm; wing ca. 0.1 mm wide. |
2n | = 16. |
= 32. |
Arabis caucasica |
Arabis oregana |
|
Phenology | Flowering Jun–Aug. | Flowering Apr–May. |
Habitat | Rare garden escape | Moist granitic soil, rocky hillsides, chaparrals, steep banks |
Elevation | 500-1000(-1400) m (1600-3300(-4600) ft) | |
Distribution |
MI; NY; BC; NB; ON; QC; YT; sw Asia [Introduced in North America] |
CA; OR
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Discussion | Arabis oregana is known from Napa and Siskiyou counties (California) and Jackson County (Oregon). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 259. | FNA vol. 7, p. 264. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | A. purpurascens, A. furcata var. purpurascens | |
Name authority | Willdenow: Enum. Pl., suppl., 45. (1814) | Rollins: Rhodora 43: 349. (1941) |
Web links |