Arabis alpina
Arabis olympica
alpine rockcress, arabis alpina
Olympics rockcress
usually simple from base, erect to ascending, often branched proximally, (0.6–)1–2(–2.5) dm.
simple or few from base (caudex), erect, unbranched, 0.7–1.1 dm, (pubescent throughout, trichomes short-stalked, forked).
petiole 0–1 cm;
blade spatulate, oblanceolate, oblong, or obovate, (0.4–)1–4(–5) cm × (3–)6–15(–20) mm, margins dentate to denticulate, apex obtuse or acute, surfaces usually pubescent, rarely subglabrate, trichomes stellate with simple rays.
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.
3–5(–6);
blade oblong or ovate, 1–3 cm × 5–15 mm, base subcordate or auriculate, margins usually dentate, rarely subentire, apex acute or obtuse.
4–6;
blade oblong, 0.6–0.8 cm × 2–3 mm, base not auriculate, margins entire, (ciliate), apex obtuse.
simple, (lax).
simple, (dense).
sepals oblong, 2.5–4(–4.7) × 1–2 mm, lateral pair conspicuously saccate basally;
petals white, spatulate to obovate, 5–8(–9) × 2–3.5 mm, apex obtuse;
filaments 3–5 mm;
anthers oblong, 0.7–1.2 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, 4–10(–12) mm.
erect, (subappressed to rachis), 5–6.5 mm, (glabrous).
ascending to spreading, torulose, 1.7–3.5(–4) cm × 1–1.7 mm;
valves each with midvein absent or obscure, along proximal 1/2;
ovules 34–50 per ovary;
style 0.3–0.6 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).
narrowly winged throughout, ovate, 1–1.4 × 0.9–1.1 mm;
wing 0.1–0.2 mm wide.
winged distally, oblong, ca. 1 × 0.5 mm;
wing ca. 0.1 mm wide.
= 16.
Arabis alpina
Arabis olympica
Arabis alpina, the generic type, is variable. It is cultivated extensively for its attractive flowers, and it sometimes escapes from cultivation. There is disagreement as to whether one or more species should be recognized in this complex. European, some African, and most North American plants are recognized as A. alpina; most of the larger-flowered, southwestern Asian plants, which are most commonly cultivated, are recognized as A. caucasica or as A. alpina subsp. caucasica (Willdenow) Briquet. In my opinion, the morphological differences between the two (see key, couplet 3) support recognition of two species, as did R. C. Rollins (1993) and G. A. Mulligan (1996).
(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.)
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
