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pinyon rock cress

nodding rock cress, rabbit-ear rockcress

Habit Perennials; usually long-lived; sexual; caudex often woody. Perennials; short- to long-lived; sexual or apomictic; caudex sometimes woody.
Stems

usually 1 per caudex branch, arising from center of rosette near ground surface, 0.9–3 dm, densely pubescent proximally, trichomes short-stalked, 5–12-rayed, 0.1–0.3 mm, sparsely pubescent to glabrescent distally.

usually 2–6 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–3(–3.7) dm, sparsely to densely pubescent proximally, trichomes simple, 0.3–0.8 mm, glabrous distally.

Basal leaves

blade linear-oblanceolate, 2–5 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5–12(–16)-rayed, 0.1–0.3 mm.

blade oblanceolate to obovate, 1.5–6 mm wide, margins usually entire, rarely dentate, ciliate throughout, trichomes (usually simple), 0.4–1 mm, surfaces pubescent, trichomes simple and short- and long-stalked, 2-rayed, 0.3–0.8 mm.

Cauline leaves

1–5, not concealing stem;

blade without auricles, surfaces of distalmost leaves pubescent.

2–10(–13), not concealing stem;

blade auricles absent or, rarely, to 0.7 mm, surfaces of distalmost leaves glabrous or margins sparsely ciliate.

Racemes

4–15(–20)-flowered, unbranched.

4–14-flowered, usually unbranched.

Flowers

ascending at anthesis;

sepals pubescent;

petals purple to lavender, 3.5–6 × 1–1.5 mm, glabrous;

pollen ellipsoid.

divaricate-ascending at anthesis;

sepals usually sparsely pubescent, rarely glabrous;

petals whitish to pale lavender, 4–6 × 1–1.5 mm, glabrous;

pollen ellipsoid or spheroid.

Fruiting pedicels

ascending, straight, 4–15(–25) mm, pubescent, trichomes appressed, branched.

divaricate-ascending to horizontal, curved or angled downward, 3–7(–10) mm, usually glabrous, rarely with some simple trichomes.

Fruits

divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 4–7.3 cm × 2.7–4 mm;

valves glabrous;

ovules 44–52 per ovary;

style 0.05–0.1 mm.

widely pendent, not appressed to rachis, not secund, curved to nearly straight, edges parallel, 2.2–4 cm × 1.2–2.1 mm;

valves glabrous;

ovules 40–70(–90) per ovary;

style 0.1–0.3(–0.5) mm.

Seeds

uniseriate, 1.9–2.3 mm in diam.;

wing continuous, 0.3–0.5 mm wide.

biseriate, 0.9–1.2 × 0.6–0.9 mm, usually not winged.

2n

= 14, 21.

Boechera dispar

Boechera pendulina

Phenology Flowering Apr–May. Flowering Apr–Jun.
Habitat Rocky slopes and gravelly soil in desert scrub and pinyon-juniper communities Rock outcrops, open gravelly flats and hillsides in sagebrush, pinyon-juniper, mountain mahogany, open conifer forests
Elevation 1500-2300 m (4900-7500 ft) 1600-3100 m (5200-10200 ft)
Distribution
from FNA
CA; NV
[BONAP county map]
from FNA
AZ; CA; CO; NV; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Boechera dispar is a distinctive sexual diploid that is known from Inyo, Mono, and San Bernardino counties, California, and Nye County, Nevada.

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

Although included in Arabis (Boechera) demissa by some authors (e.g., S. L. Welsh et al. 2003; N. H. Holmgren 2005b), B. pendulina is readily distinguished from that species (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). Typical collections are sexual diploids, whereas the type of var. russeola is a triploid apomict; further study is needed to determine if the two are conspecific.

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

Source FNA vol. 7, p. 374. FNA vol. 7, p. 395.
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. 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
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. 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 dispar, Arabis juniperina, Arabis nardina, Arabis salubris Arabis pendulina, Arabis demissa var. russeola, Arabis diehlii, Arabis pendulina var. russeola, Arabis setulosa, B. demissa var. pendulina, B. demissa var. russeola, B. pendulina var. russeola
Name authority (M. E. Jones) Al-Shehbaz: Novon 13: 384. (2003) (Greene) W. A. Weber: Phytologia 51: 370. (1982)
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