Arabis modesta
Arabis olympica
modest rock-cress, Rogue Canyon rock-cress
Olympics rockcress
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).
simple or few from base (caudex), erect, unbranched, 0.7–1.1 dm, (pubescent throughout, trichomes short-stalked, forked).
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.
petiole 0.3–0.6 cm, (sparsely ciliate);
blades oblanceolate to obovate, 0.4–1cm × 2–7 mm, margins entire or repand, (ciliate), apex obtuse, surfaces sparsely pubescent, trichomes simple and forked.
(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.
4–6;
blade oblong, 0.6–0.8 cm × 2–3 mm, base not auriculate, margins entire, (ciliate), apex obtuse.
simple, (dense).
simple, (dense).
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.
sepals (greenish), ovate, 1.5 × 0.5 mm, lateral pair not saccate basally, (glabrous);
petals white, oblanceolate, 3.5–4 × 1 mm, apex rounded.
ascending to divaricate, 7–18(–25) mm.
erect, (subappressed to rachis), 5–6.5 mm, (glabrous).
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.
erect, (appressed to rachis), slightly torulose, 2–2.3 cm × 1 mm;
valves each with distinct midvein extending full length;
ovules 28–34 per ovary;
style 0.2–0.3 mm, (stout).
winged distally, oblong, 1.7–2.2 × 0.9–1.2 mm;
wing 0.2–0.5 mm wide.
winged distally, oblong, ca. 1 × 0.5 mm;
wing ca. 0.1 mm wide.
= 32.
Arabis modesta
Arabis olympica
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.)
Arabis olympica, which is known from two collections, J. B. Flett s.n. (holotype, US; isotype, WS) and N. Buckingham 1577 (WS) that were made from Jefferson and Clallam counties, respectively, was reduced by R. C. Rollins (1936, 1941, 1993) to a variety of A. furcata. An examination of the type collections of both species reveals that they are distinct. Although the fruits and seeds of A. olympica are not fully mature, they are clearly different in width and orientation from those of A. furcata at the same developmental stage. The striking differences in fruit width and orientation, stem indument, and seed and flower size support their maintenance as distinct species. Although both species grow in Washington, the range of A. olympica seems to be restricted to Clallam and Jefferson counties and is disjunct from Chelan, Kittitas, and Yakima counties, where A. furcata grows.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
WA
