Boechera subpinnatifida |
Boechera lyallii |
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ashy rock-cress, Klamath rockcress |
jewelled suncress, Lyall's rockcress, Lyall's slender rock-cress, murry's rockcress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Perennials; long-lived; (cespitose); sexual or apomictic; caudex woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4(–5) dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.1–0.2 mm, sparsely pubescent distally. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.5(–2) dm, glabrous throughout. |
Basal leaves | blade narrowly oblanceolate, 1–4(–5) mm wide, margins prominently dentate to subpinnatifid (leaf margins of sterile shoots often entire), ciliate near petiole base, trichomes (simple or 2-rayed), 0.4–0.6 mm, surfaces densely pubescent, trichomes short-stalked, (2–)4–9-rayed, 0.05–0.2 mm. |
blade linear-oblanceolate, 1–5(–8) mm wide, margins entire, usually ciliate at least proximally, trichomes (simple and/or short-stalked, 2- or 3-rayed), 0.1–0.3 mm, surfaces (sometimes the entire leaf) usually glabrous or (rarely, the youngest leaves of sterile shoots) pubescent, trichomes 4–6-rayed, 0.05–0.1 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
1–5, usually not concealing stem; blade auricles 0.5–1.5 mm or, rarely, absent, surfaces glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
2–10(–15)-flowered, unbranched. |
Flowers | divaricate-ascending to pendent at anthesis; sepals pubescent; petals usually purple, rarely lavender, 9–14 × 1.5–3 mm, glabrous; pollen ellipsoid. |
erect at anthesis; sepals glabrous; petals lavender to purplish, 6–8.5 × 1.5–3 mm, glabrous; pollen ellipsoid or spheroid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
erect, straight, 3–8(–15) mm, glabrous. |
Fruits | pendent, not appressed to rachis, not secund, straight to slightly curved, edges parallel, (3.5–)5–8 cm × (1.6–)2–3 mm; valves pubescent throughout; ovules 24–42 per ovary; style 0.5–1 mm. |
erect, appressed to rachis, not secund, straight, edges parallel, 3–5.6 cm × 1.5–2.5 mm; valves glabrous; ovules 34–64 per ovary; style 0.1–0.7 mm. |
Seeds | uniseriate, 2.5–3.5 × 1.5–2.2 mm; wing continuous or at both ends, 0.4–0.8 mm wide. |
biseriate or sub-biseriate, 1.5–2 × 1–1.5 mm; wing continuous, 0.3–0.5 mm wide. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera lyallii |
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Phenology | Flowering Mar–May. | Flowering Jun–Aug. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Cliffs, talus slopes, gravelly soil in alpine and subalpine habitats |
Elevation | 800-2400 m (2600-7900 ft) | 1400-3700 m (4600-12100 ft) |
Distribution |
CA; ID; NV; OR; UT
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CA; ID; MT; NV; OR; UT; WA; BC; YT
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Discussion | Originally thought to be restricted to northern California and adjacent Oregon, Boechera subpinnatifida is a sexual species that recently has been found in central Idaho, northern Nevada, and northwestern Utah. It appears to intergrade with both B. puberula and B. retrofracta, and species boundaries within this complex need further study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The taxon traditionally treated as Arabis (Boechera) lyallii var. nubigena is here segregated as B. paupercula (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). Completely glabrous individuals of B. lyallii are sometimes confused with B. davidsonii, but they are easily distinguished by the absence of persistent leaf bases on caudex branches, erect and appressed (versus ascending) fruits, and biseriate to sub-biseriate (versus uniseriate) seeds. Both sexual and apomictic collections are known; further study is needed to determine whether they truly are conspecific. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 409. | FNA vol. 7, p. 389. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis lyallii, Arabis armerifolia, Arabis densa, Arabis drummondii var. alpina, Arabis drummondii var. lyallii, Arabis multiceps, Arabis murrayi |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (S. Watson) Dorn: Vasc. Pl. Wyoming ed. 3, 376. (2001) |
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