Boechera lyallii

(S. Watson) Dorn

Vasc. Pl. Wyoming ed. 3, 376. 2001.

Basionym: Arabis lyallii S. Watson Proc. Amer. Acad. Arts 11: 122. 1876
Synonyms: Arabis armerifolia Greene Arabis densa Greene Arabis drummondii var. alpina S. Watson Arabis drummondii var. lyallii (S. Watson) Jepson Arabis multiceps G. A. Mulligan Arabis murrayi
Treatment appears in FNA Volume 7. Treatment on page 389. Mentioned on page 351, 355, 368, 372, 373, 392, 394.

Perennials; long-lived; (cespitose); sexual or apomictic; caudex woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.5(–2) dm, glabrous throughout. Basal leaves: 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: 1–5, usually not concealing stem; blade auricles 0.5–1.5 mm or, rarely, absent, surfaces glabrous. Racemes 2–10(–15)-flowered, unbranched. Fruiting pedicels erect, straight, 3–8(–15) mm, glabrous. Flowers erect at anthesis; sepals glabrous; petals lavender to purplish, 6–8.5 × 1.5–3 mm, glabrous; pollen ellipsoid or spheroid. Fruits 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 biseriate or sub-biseriate, 1.5–2 × 1–1.5 mm; wing continuous, 0.3–0.5 mm wide.

Phenology: Flowering Jun–Aug.
Habitat: Cliffs, talus slopes, gravelly soil in alpine and subalpine habitats
Elevation: 1400-3700 m


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B.C., Yukon, Calif., Idaho, Mont., Nev., Oreg., Utah, Wash.


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.

Selected References


Lower Taxa

... more about "Boechera lyallii"
Ihsan A. Al-Shehbaz +  and Michael D. Windham +
(S. Watson) Dorn +
Arabis lyallii +
B.C. +, Yukon +, Calif. +, Idaho +, Mont. +, Nev. +, Oreg. +, Utah +  and Wash. +
1400-3700 m +
Cliffs, talus slopes, gravelly soil in alpine and subalpine habitats +
Flowering Jun–Aug. +
Vasc. Pl. Wyoming ed. +
Arabis armerifolia +, Arabis densa +, Arabis drummondii var. alpina +, Arabis drummondii var. lyallii +, Arabis multiceps +  and Arabis murrayi +
Boechera lyallii +
Boechera +
species +