Arabis oregana
Arabis modesta
Oregon rock-cress
modest rock-cress, Rogue Canyon rock-cress
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).
simple or few from base (caudex), erect, usually unbranched, rarely branched (few) distally, 2.2–5.5(–6.7) dm, (usually pubescent throughout, rarely subglabrate distally, trichomes stellate).
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.
petiole 1–4(–5) cm, (rarely minutely ciliate near base);
blade oblanceolate to obovate, (0.8–)2–4.5(–6) cm × (4–)10–20(–25) mm, margins entire, repand, or dentate, (not ciliate), apex obtuse, surfaces pubescent, trichomes short-stalked, stellate.
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.
(2–)4–6(–9);
blade oblong or ovate, 1–3.5(–4.5) cm × (3–)6–10(–20) mm, base not auriculate, margins entire, repand, or dentate, apex obtuse or acute, surfaces pubescent, trichomes short-stalked, stellate.
simple, (dense).
simple, (dense).
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.
sepals (purple), oblong, (4–)5–6.5(–8) × 1.5–2 mm, lateral pair saccate basally;
petals purple, spatulate, (10–)12–16(–20) × 4–6(–7) mm, apex rounded;
filaments (4–)5–8 mm;
anthers narrowly oblong, 1.3–2 mm.
ascending to erect, 5–10 mm, (pubescent or glabrous).
ascending to divaricate, 7–18(–25) 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.
suberect to divaricate, sometimes slightly curved, slightly torulose, (2.8–)3.5–6 cm × 1.5–2 mm;
valves each with prominent midvein extending to middle or full length;
ovules 20–34 per ovary;
style 0.5–1(–1.5) mm.
narrowly winged distally or not winged, oblong, 1.8–2.2 × ca. 1 mm;
wing ca. 0.1 mm wide.
winged distally, oblong, 1.7–2.2 × 0.9–1.2 mm;
wing 0.2–0.5 mm wide.
= 32.
= 32.
Arabis oregana
Arabis modesta
Arabis oregana is known from Napa and Siskiyou counties (California) and Jackson County (Oregon).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Arabis modesta, known only from Napa, Siskiyou, and Yolo counties (California), and Jackson and Josephine counties (Oregon), and the following four species form a well-defined group easily separated from the first nine species above by their large, purple petals. Arabis modesta is readily distinguished from other purple-flowered Arabis by having very fine, short-stalked cruciform and 3-rayed, instead of simple and 2-rayed, forked trichomes. Arabis blepharophylla has broadly winged, orbicular seeds, and the other purple-flowered species (A. aculeolata, A. mcdonaldiana, A. oregana) have oblong seeds that are not winged or narrowly winged distally. The lines separating these three species are not as well-defined as those of A. blepharophylla and A. modesta, and further studies are needed to resolve them. I prefer to maintain all five species of purple-flowered Arabis as distinct until thorough molecular and hybridization studies are conducted. In the absence of such studies, it is unwise to make any nomenclatural changes.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
