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Brewer's rock-cress

Habit Perennials; long-lived; sexual; caudex woody.
Stems

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, 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

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

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

Racemes

7–20(–30)-flowered, usually unbranched.

Flowers

ascending at anthesis;

sepals pubescent;

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

pollen ellipsoid.

Fruiting pedicels

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

Fruits

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, 1.2–1.7 × 1–1.2 mm;

wing continuous, 0.1–0.2 mm wide distally.

Boechera breweri

Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

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. 367.
Parent taxa Brassicaceae > tribe Boechereae > Boechera
Sibling taxa
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 breweri, Arabis breweri var. figularis, Arabis epilobioides
Name authority (S. Watson) Al-Shehbaz: Novon 13: 384. (2003)
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