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Blue Mountain rockcress, hoary rock-cress, silver rockcress

Brewer's rock-cress

Habit Perennials; short-lived; sexual; caudex not woody. Perennials; long-lived; sexual; caudex woody.
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, somewhat elevated on woody base or from ground surface, 0.6–3.5(–4.5) dm, densely pubescent proximally, trichomes long-stalked and simple, 2-rayed (sometimes all simple), 0.4–1 mm, sparsely pubescent or glabrous distally.

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, 3–7(–11) mm wide, margins entire or dentate, ciliate proximally, trichomes to 1 mm, surfaces densely pubescent, trichomes long-stalked, 2–4-rayed, 0.4–0.8 mm.

Cauline leaves

7–45(–65), concealing stem proximally;

blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent.

5–15(–28), often concealing stem proximally;

blade auricles 0.5–3(–5) mm, surfaces of distalmost leaves pubescent.

Racemes

10–40(–64)-flowered, usually unbranched.

7–20(–30)-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.

ascending at anthesis;

sepals pubescent;

petals usually purple (rarely lavender), 7–12 × 2–4 mm, glabrous;

pollen ellipsoid.

Fruiting pedicels

pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched.

ascending to divaricate-ascending, straight, 3–25 mm, pubescent or glabrous, trichomes spreading, simple and 2-rayed.

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.

ascending to divaricate-ascending, not appressed to rachis, not secund, usually curved, rarely straight, edges parallel, 3.5–10 cm × 1.5–2.2 mm;

valves usually glabrous, rarely sparsely pubescent;

ovules 48–96 per ovary;

style 0.05–0.3 mm.

Seeds

uniseriate, 1.4–1.8 × 1–1.4 mm;

wing continuous, 0.1–0.3 mm wide.

uniseriate, 1.2–1.7 × 1–1.2 mm;

wing continuous, 0.1–0.2 mm wide distally.

2n

= 14.

Boechera puberula

Boechera breweri

Phenology Flowering Apr–Jul.
Habitat Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities
Elevation 1300-2900 m (4300-9500 ft)
Distribution
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[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.)

Subspecies 2 (2 in the flora).

Relatively few other sexual diploid species of Boechera co-occur with B. breweri, and the only currently recognized hybrid involving this taxon is B. rubicundula (= B. arcuata × B. breweri; M. D. Windham and I. A. Al-Shehbaz 2007). Boechera breweri appears to be related to B. sparsiflora, and some specimens of subsp. shastaensis can be difficult to separate from that species. The two subspecies appear to intergrade on the western side of the Sacramento Valley from Tehama to Solano counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stems 0.6-2 dm, pubescent distally; fruiting pedicels 3-8(-12) mm, pubescent; fruits 3.5-7.5 cm.
subsp. breweri
1. Stems 1.8-3.5(-4.5) dm, glabrous distally; fruiting pedicels (7-)10-25 mm, usually glabrous; fruits (4.5-)7-10 cm.
subsp. shastaensis
Source FNA vol. 7, p. 399. FNA vol. 7, p. 367.
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. 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. 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
Subordinate taxa
B. breweri subsp. breweri, B. breweri subsp. shastaensis
Synonyms Arabis puberula, Arabis arida, Arabis beckwithii, Arabis lignipes var. impar, Arabis sabulosa, Arabis subpinnatifida var. beckwithii, Arabis subpinnatifida var. impar, B. beckwithii Arabis breweri, Arabis breweri var. figularis, Arabis epilobioides
Name authority (Nuttall) Dorn: Brittonia, 55: 3. (2003) (S. Watson) Al-Shehbaz: Novon 13: 384. (2003)
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