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Blue Mountain rockcress, hoary rock-cress, silver rockcress

Mount Adams rock-cress, Mt. Adams rock-cress

Habit Perennials; short-lived; sexual; caudex not woody. Perennials; long-lived; (cespitose); apomictic; caudex usually 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.

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 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 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

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

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

4–8, not concealing stem;

blade auricles 1–2 mm, surfaces of distalmost leaves glabrous.

Racemes

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

5–12(–18)-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 glabrous;

petals lavender to purple, 4–5.5 × 1–1.5 mm, glabrous;

pollen spheroid.

Fruiting pedicels

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

usually divaricate-ascending, rarely horizontal, straight, 2–5(–10) mm, glabrous.

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.

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, 1.4–1.8 × 1–1.4 mm;

wing continuous, 0.1–0.3 mm wide.

uniseriate, 1.1–1.5 × 0.9–1.3 mm;

wing continuous, 0.1–0.3 mm wide.

2n

= 14.

Boechera puberula

Boechera paddoensis

Phenology Flowering Apr–Jul. Flowering Jul–Aug.
Habitat Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities Rocky ridges
Elevation 1300-2900 m (4300-9500 ft) 1500-2100 m (4900-6900 ft)
Distribution
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
OR; WA
[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.)

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.

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

Source FNA vol. 7, p. 399. FNA vol. 7, p. 392.
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. 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. 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 lemmonii var. paddoensis
Name authority (Nuttall) Dorn: Brittonia, 55: 3. (2003) (Rollins) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 268. (2007)
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