Boechera paddoensis

(Rollins) Windham & Al-Shehbaz

Harvard Pap. Bot. 11: 268. 2007.

Basionym: Arabis lemmonii var. paddoensis Rollins Rhodora 43: 384. 1941
Treatment appears in FNA Volume 7. Treatment on page 392. Mentioned on page 356.

Perennials; long-lived; (cespitose); apomictic; caudex usually woody. Stems 1–3 per caudex branch, arising from center of rosette near ground surface, or arising laterally proximal to sterile shoots, 1–2.5 dm, glabrous throughout. Basal leaves: blade narrowly oblanceolate, 1–3(–6) mm wide, margins usually entire, rarely apically few-toothed, not ciliate, surfaces sparsely pubescent, trichomes short-stalked, 4–8-rayed, 0.08–0.2 mm. Cauline leaves: 4–8, not concealing stem; blade auricles 1–2 mm, surfaces of distalmost leaves glabrous. Racemes 5–12(–18)-flowered, usually unbranched. Fruiting pedicels usually divaricate-ascending, rarely horizontal, straight, 2–5(–10) mm, glabrous. Flowers ascending at anthesis; sepals glabrous; petals lavender to purple, 4–5.5 × 1–1.5 mm, glabrous; pollen spheroid. Fruits usually divaricate-ascending, rarely horizontal, not appressed to rachis, secund (often weakly so), straight, edges parallel, 3–5.5 cm × 1.5–2 mm; valves glabrous; ovules 42–54 per ovary; style 0.05–0.1 mm. Seeds uniseriate, 1.1–1.5 × 0.9–1.3 mm; wing continuous, 0.1–0.3 mm wide.


Phenology: Flowering Jul–Aug.
Habitat: Rocky ridges
Elevation: 1500-2100 m

Distribution

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Oreg., Wash.

Discussion

Morphological evidence suggests that Boechera paddoensis is an apomictic species that arose through hybridization between B. lemmonii and B. lyallii (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). Boechera paddoensis is known only from the mountains of central Washington and northeastern Oregon.

Selected References

None.

Lower Taxa

None.