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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
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
NV; UT
[BONAP county map]
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
B. acutina, B. arcuata, B. atrorubens, B. bodiensis, B. breweri, B. burkii, B. calderi, B. californica, B. canadensis, B. cascadensis, B. cobrensis, B. collinsii, B. consanguinea, B. constancei, B. covillei, B. crandallii, B. cusickii, B. davidsonii, B. dentata, B. depauperata, B. dispar, B. divaricarpa, B. drepanoloba, B. duchesnensis, B. elkoensis, B. evadens, B. falcatoria, B. falcifructa, B. fecunda, B. fendleri, B. fernaldiana, B. formosa, B. fructicosa, B. glareosa, B. glaucovalvula, B. goodrichii, B. gracilenta, B. gracilipes, B. grahamii, B. gunnisoniana, B. harrisonii, B. hastatula, B. hoffmannii, B. holboellii, B. horizontalis, B. howellii, B. inyoensis, B. johnstonii, B. koehleri, B. laevigata, B. languida, B. lasiocarpa, B. lemmonii, B. lignifera, B. lincolnensis, B. lyallii, B. macounii, B. microphylla, B. missouriensis, B. nevadensis, B. ophira, B. oxylobula, B. paddoensis, B. pallidifolia, B. parishii, B. pauciflora, B. paupercula, B. peirsonii, B. pendulina, B. pendulocarpa, B. perennans, B. perstellata, B. pinetorum, B. pinzliae, B. platysperma, B. polyantha, B. porphyrea, B. pratincola, B. pulchra, B. pusilla, B. pygmaea, B. quebecensis, B. rectissima, B. repanda, B. retrofracta, B. rigidissima, B. rollei, B. rollinsiorum, B. rubicundula, B. saximontana, B. schistacea, B. serotina, B. serpenticola, B. shevockii, B. shockleyi, B. sparsiflora, B. spatifolia, B. stricta, B. subpinnatifida, B. suffrutescens, B. texana, B. tiehmii, B. tularensis, B. ultra-alsa, B. villosa, B. williamsii, B. xylopoda, B. yorkii
B. acutina, B. arcuata, B. atrorubens, B. bodiensis, B. breweri, B. burkii, B. calderi, B. californica, B. canadensis, B. cascadensis, B. cobrensis, B. collinsii, B. consanguinea, B. constancei, B. covillei, B. crandallii, B. cusickii, B. davidsonii, B. dentata, B. depauperata, B. dispar, B. divaricarpa, B. drepanoloba, B. duchesnensis, B. elkoensis, B. evadens, B. falcatoria, B. falcifructa, B. fecunda, B. fendleri, B. fernaldiana, B. formosa, B. fructicosa, B. glareosa, B. glaucovalvula, B. gracilenta, B. gracilipes, B. grahamii, B. gunnisoniana, B. harrisonii, B. hastatula, B. hoffmannii, B. holboellii, B. horizontalis, B. howellii, B. inyoensis, B. johnstonii, B. koehleri, B. laevigata, B. languida, B. lasiocarpa, B. lemmonii, B. lignifera, B. lincolnensis, B. lyallii, B. macounii, B. microphylla, B. missouriensis, B. nevadensis, B. ophira, B. oxylobula, B. paddoensis, B. pallidifolia, B. parishii, B. pauciflora, B. paupercula, B. peirsonii, B. pendulina, B. pendulocarpa, B. perennans, B. perstellata, B. pinetorum, B. pinzliae, B. platysperma, B. polyantha, B. porphyrea, B. pratincola, B. puberula, B. pulchra, B. pusilla, B. pygmaea, B. quebecensis, B. rectissima, B. repanda, B. retrofracta, B. rigidissima, B. rollei, B. rollinsiorum, B. rubicundula, B. saximontana, B. schistacea, B. serotina, B. serpenticola, B. shevockii, B. shockleyi, B. sparsiflora, B. spatifolia, B. stricta, B. subpinnatifida, B. suffrutescens, B. texana, B. tiehmii, B. tularensis, B. ultra-alsa, B. villosa, B. williamsii, B. xylopoda, B. yorkii
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)
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