Boechera howellii

(S. Watson) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 69. 2006

Basionyms: Arabis howellii S. Watson Proc. Amer. Acad. Arts 25: 124. 1890
Synonyms: Arabis conferta Greene Arabis inamoena var. acutata Jepson Arabis platyloba Greene Arabis platysperma var. howellii (S. Watson) Jepson Arabis platysperma var. imparata Jepson
Treatment appears in FNA Volume 7. Treatment on page 384. Mentioned on page 351, 356, 372, 398.
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Perennials; long-lived; sexual; caudex usually woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.6–2(–3) dm, glabrous throughout. Basal leaves: blade narrowly oblanceolate, 1–7 mm wide, margins entire, ciliate proximally, trichomes (simple mixed with a few short-stalked, 2-rayed ones) 0.1–0.4 mm, surfaces glabrous. Cauline leaves: 2–4, not concealing stem; blade auricles (0–)0.2–1 mm, surfaces of distalmost leaves usually glabrous, rarely ciliate proximally. Racemes 2–5-flowered, unbranched. Fruiting pedicels ascending, straight, 4–10 mm, glabrous. Flowers erect to ascending at anthesis; sepals glabrous; petals white to dark lavender, 4–8 × 1–2.5 mm, glabrous; pollen ellipsoid. Fruits suberect to ascending, usually not appressed to rachis, not secund, straight to curved, edges often somewhat undulate (not parallel), 2.5–6.5 cm × 3–7 mm; valves glabrous; ovules 10–20 per ovary; style 0.05–0.3 mm. Seeds uniseriate, 3–6 × 2–4 mm; wing continuous, 1.3–2.5 mm wide.

Phenology: Flowering Jun–Aug.
Habitat: Rock outcrops, talus slopes and gravelly soil in alpine and subalpine habitats
Elevation: 1800-3800 m

Discussion

Boechera howellii usually is subsumed under B. platysperma, but the two taxa are distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison).

References

None.

Lower Taxa

No lower taxa listed.