The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links
Boechera subpinnatifida

ashy rock-cress, Klamath rockcress

Howell's flat-seed rock-cress, Howell's rockcress, pioneer rock-cress

Habit Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). Perennials; long-lived; sexual; caudex usually woody.
Stems

usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4(–5) dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.1–0.2 mm, sparsely pubescent distally.

usually 1 per caudex branch, arising from center of rosette near ground surface, 0.6–2(–3) dm, glabrous throughout.

Basal leaves

blade narrowly oblanceolate, 1–4(–5) mm wide, margins prominently dentate to subpinnatifid (leaf margins of sterile shoots often entire), ciliate near petiole base, trichomes (simple or 2-rayed), 0.4–0.6 mm, surfaces densely pubescent, trichomes short-stalked, (2–)4–9-rayed, 0.05–0.2 mm.

blade narrowly oblanceolate, 1–7 mm wide, margins entire, ciliate proximally, trichomes (simple mixed with a few short-stalked, 2-rayed ones) 0.1–0.4 mm, surfaces glabrous.

Cauline leaves

(10–)20–60, often concealing stem throughout;

blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent.

2–4, not concealing stem;

blade auricles (0–)0.2–1 mm, surfaces of distalmost leaves usually glabrous, rarely ciliate proximally.

Racemes

8–30-flowered, usually unbranched.

2–5-flowered, unbranched.

Flowers

divaricate-ascending to pendent at anthesis;

sepals pubescent;

petals usually purple, rarely lavender, 9–14 × 1.5–3 mm, glabrous;

pollen ellipsoid.

erect to ascending at anthesis;

sepals glabrous;

petals white to dark lavender, 4–8 × 1–2.5 mm, glabrous;

pollen ellipsoid.

Fruiting pedicels

reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched.

ascending, straight, 4–10 mm, glabrous.

Fruits

pendent, not appressed to rachis, not secund, straight to slightly curved, edges parallel, (3.5–)5–8 cm × (1.6–)2–3 mm;

valves pubescent throughout;

ovules 24–42 per ovary;

style 0.5–1 mm.

suberect to ascending, usually not appressed to rachis, not secund, straight to curved, edges often somewhat undulate (not parallel), 2.5–6.5 cm × 3–7 mm;

valves glabrous;

ovules 10–20 per ovary;

style 0.05–0.3 mm.

Seeds

uniseriate, 2.5–3.5 × 1.5–2.2 mm;

wing continuous or at both ends, 0.4–0.8 mm wide.

uniseriate, 3–6 × 2–4 mm;

wing continuous, 1.3–2.5 mm wide.

2n

= 14.

Boechera subpinnatifida

Boechera howellii

Phenology Flowering Mar–May. Flowering Jun–Aug.
Habitat Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities Rock outcrops, talus slopes and gravelly soil in alpine and subalpine habitats
Elevation 800-2400 m (2600-7900 ft) 1800-3800 m (5900-12500 ft)
Distribution
from FNA
CA; ID; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Originally thought to be restricted to northern California and adjacent Oregon, Boechera subpinnatifida is a sexual species that recently has been found in central Idaho, northern Nevada, and northwestern Utah. It appears to intergrade with both B. puberula and B. retrofracta, and species boundaries within this complex need further study.

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

Boechera howellii usually is subsumed under B. platysperma, but the two taxa are distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison).

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

Source FNA vol. 7, p. 409. FNA vol. 7, p. 384.
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. 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. 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. 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 subpinnatifida Arabis howellii, Arabis conferta, Arabis inamoena var. acutata, Arabis platyloba, Arabis platysperma var. howellii, Arabis platysperma var. imparata
Name authority (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) (S. Watson) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 69. (2006)
Web links