Boechera puberula |
Boechera goodrichii |
|
---|---|---|
Blue Mountain rockcress, hoary rock-cress, silver rockcress |
|
|
Habit | Perennials; short-lived; sexual; caudex not woody. | Biennials or perennials; short-lived; apomictic; caudex present or absent. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, (1–)2–6.3 dm, densely pubescent proximally, trichomes short-stalked, 3–8-rayed, 0.1–0.3(–0.5) mm, similarly pubescent distally. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 2.6–7.4(–10.2) dm, densely pubescent proximally, trichomes short-stalked, 4–8-rayed, 0.1–0.5 mm, sometimes mixed with 2- or 3-rayed ones, to 1 mm, usually sparsely pubescent distally, rarely glabrous. |
Basal leaves | blade oblanceolate to linear-oblanceolate, 1.5–5 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5–12-rayed, 0.05–0.2 mm. |
blade oblanceolate, 3–8(–10) mm wide, margins entire or shallowly dentate, ciliate near petiole base, trichomes (simple), to 1 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–8-rayed, 0.15–0.4 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
22–72, concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
25–112-flowered, usually unbranched. |
Flowers | ascending to descending at anthesis; sepals pubescent; petals white to lavender, 5–9 × 0.8–1.8 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals pubescent; petals white to lavender, 6–8 × 1–1.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched. |
divaricate-descending, straight or gently curved, (10–)15–28 mm, usually sparsely pubescent, rarely glabrous, trichomes appressed, branched. |
Fruits | closely pendent, rarely appressed to rachis, sometimes somewhat secund, usually straight, edges parallel, 3–6.5 cm × 1.9–2.2 mm; valves pubescent throughout; ovules 38–64 per ovary; style 0.05–0.1 mm. |
pendent, not appressed to rachis, not secund, straight or gently curved, edges parallel, 4.5–6.5 cm × 1.5–3 mm; valves glabrous; ovules 100–136 per ovary; style to 0.2 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
biseriate or sub-biseriate, 1–1.4 × 0.9–1 mm; wing continuous, 0.05–0.15 mm. |
2n | = 14. |
|
Boechera puberula |
Boechera goodrichii |
|
Phenology | Flowering Apr–Jul. | Flowering Apr–May. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Rocky slopes in sagebrush, pinyon-juniper woodlands, oak thickets |
Elevation | 1300-2900 m (4300-9500 ft) | 1300-2300 m (4300-7500 ft) |
Distribution |
CA; NV; OR; UT
|
NV; UT |
Discussion | Boechera puberula is a diploid species that appears to intergrade with both B. retrofracta and B. subpinnatifida. The glabrous-fruited specimens discussed by R. C. Rollins (1993) represent apomictic hybrids with other species, primarily B. pendulocarpa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Morphological evidence suggests that Boechera goodrichii is an apomictic species that arose through hybridization between B. gracilipes and B. retrofracta. Some specimens of it originally were identified as Arabis holboellii var. pinetorum (= B. pinetorum), but they are most similar to B. consanguinea (see M. D. Windham and I. A. Al-Shehbaz 2007, 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 399. | FNA vol. 7, p. 380. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis puberula, Arabis arida, Arabis beckwithii, Arabis lignipes var. impar, Arabis sabulosa, Arabis subpinnatifida var. beckwithii, Arabis subpinnatifida var. impar, B. beckwithii | Arabis goodrichii |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | (S. L. Welsh) N. H. Holmgren: in A. Cronquist et al., Intermount. Fl. 2(B): 364. (2005) |
Web links |
|