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Blue Mountain rockcress, hoary rock-cress, silver rockcress

desert rockcress

Habit Perennials; short-lived; sexual; caudex not woody. Perennials; short- to long-lived; apomictic or sexual; 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.

usually 2–5 per caudex branch, arising laterally proximal to sterile shoots, often elevated on woody base, 1.2–4(–5) dm, densely pubescent proximally, trichomes short-stalked, 4–7-rayed, 0.1–0.3 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 narrowly oblanceolate, 2–5(–8) mm wide, margins entire, rarely ciliate near petiole base, trichomes (simple or spurred), to 1 mm, surfaces densely pubescent, trichomes short-stalked, 3–7-rayed, 0.05–0.3 mm.

Cauline leaves

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

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

4–12(–17), rarely concealing stem proximally;

blade auricles 0.5–2 mm, surfaces of distalmost leaves sparsely pubescent.

Racemes

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

6–15(–25)-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 whitish (often aging pale lavender), 5–7 × 1–1.5 mm, glabrous;

pollen ellipsoid or spheroid.

Fruiting pedicels

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

slightly descending, gently recurved, 5–16 mm, glabrous or sparsely pubescent, 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.

widely pendent, not appressed to rachis, not secund, usually curved, edges parallel, 2.5–5.6 cm × 1.2–2 mm;

valves glabrous;

ovules 48–74 per ovary;

style 0.1–0.2 mm.

Seeds

uniseriate, 1.4–1.8 × 1–1.4 mm;

wing continuous, 0.1–0.3 mm wide.

uniseriate, 1–1.3 × 0.8–1 mm;

wing often continuous, 0.1–0.15 mm wide.

2n

= 14.

= 14.

Boechera puberula

Boechera lignifera

Phenology Flowering Apr–Jul. Flowering Apr–May.
Habitat Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities Rocky slopes and sandy soil in sagebrush and pinyon-juniper woodlands
Elevation 1300-2900 m (4300-9500 ft) 1700-2300 m (5600-7500 ft)
Distribution
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; ID; NM; UT; WY
[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.)

Boechera lignifera is commonly found on stabilized sand dunes. The related B. cobrensis often is found in similar habitats, and the two species can be difficult to distinguish where their ranges overlap in Idaho and Wyoming. It is possible that B. cobrensis was involved in the origin of some apomictic populations currently assigned to B. lignifera.

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

Source FNA vol. 7, p. 399. FNA vol. 7, p. 388.
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. 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 lignifera
Name authority (Nuttall) Dorn: Brittonia, 55: 3. (2003) (A. Nelson) W. A. Weber: Phytologia 51: 370. (1982)
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