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black-flower rockcress, dark-red-flower rockcress, purple sickle-pod rock-cress, sicklepod rockcress

elegant rockcress, sickle-pod rock-cress, slender rockcress, stretching suncress

Habit Perennials; usually short-lived; sexual; caudex not woody. Biennials or perennials; short-lived; sexual; caudex present or absent.
Stems

usually 1 per caudex branch, arising from center of rosette near ground surface, 0.8–6 dm, sparsely pubescent proximally, trichomes short-stalked and simple, (scattered), 2-rayed, 0.1–0.15 mm, glabrous distally.

usually 1 per caudex branch, arising from center of rosette near ground surface, 3–8 dm, densely pubescent proximally, trichomes simple mixed with fewer short-stalked, 2-rayed ones, 0.4–1.5 mm, glabrous or sparsely pubescent distally.

Basal leaves

blade oblanceolate, 4–10 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 3- or 4-rayed, 0.1–0.2 mm.

blade oblanceolate or linear-oblanceolate, 3–12 mm wide, margins usually entire, rarely dentate, ciliate proximally, trichomes (usually simple), to 1 mm, surfaces densely pubescent, trichomes short-stalked, 2–5-rayed, 0.3–0.8 mm.

Cauline leaves

7–25, concealing stem proximally;

blade auricles 1–4 mm, surfaces of distalmost leaves glabrous.

(9–)15–35, often concealing stem proximally;

blade auricles 3–10 mm, surfaces of distalmost leaves glabrous, sometimes margins ciliate.

Racemes

6–20-flowered, usually unbranched.

12–50-flowered, usually unbranched.

Flowers

ascending at anthesis;

sepals pubescent;

petals dark reddish purple (drying indigo), 7–9 × 1.5–2 mm, glabrous;

pollen ellipsoid.

ascending at anthesis;

sepals sparsely pubescent;

petals usually lavender to purple, rarely white, 7–13 × 2–5 mm, glabrous;

pollen ellipsoid.

Fruiting pedicels

ascending, usually straight, 5–10 mm, glabrous or pubescent, trichomes spreading, simple.

usually ascending, rarely almost horizontal, straight or slightly recurved, 3–10(–18) mm, usually pubescent, rarely glabrous, trichomes spreading, usually simple.

Fruits

ascending, not appressed to rachis, not secund, curved or straight, edges parallel, (4–)6–12 cm × 1.7–2.2 mm;

valves glabrous;

ovules 80–100 per ovary;

style 0.2–0.5 mm.

usually ascending, rarely almost horizontal, not appressed to rachis, not secund, usually curved, edges parallel, 5–13 cm × 1.7–2 mm;

valves glabrous;

ovules 90–170 per ovary;

style 0.05–0.3 mm.

Seeds

uniseriate, 1.2–1.7 × 0.9–1.2 mm;

wing lateral and distal, 0.1–0.2 mm wide.

uniseriate, 1.5–2 × 1–1.5 mm;

wing continuous, 0.1–0.2 mm wide.

2n

= 14.

Boechera atrorubens

Boechera sparsiflora

Phenology Flowering Apr–May. Flowering Apr–Jun.
Habitat Rocky summits and sandy loam on sagebrush slopes Rocky slopes, clay hills, sandy soil in sagebrush and mountain shrub communities, meadows, and open conifer forests
Elevation ca. 600 m (ca. 2000 ft) 400-2800 m (1300-9200 ft)
Distribution
from FNA
OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; NV; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Boechera atrorubens is often treated as a variety of B. sparsiflora (e.g., R. C. Rollins 1993), it is readily separated from that species by having proximal stems sparsely (versus densely) pubescent with much smaller (0.15 versus 1.5 mm) trichomes. The two taxa rarely grow in proximity and, in areas where they are sympatric, B. atrorubens is further distinguished by its narrower (1.5–2 versus 2–5 mm) petals that are dark reddish purple to indigo (versus lavender or white).

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

As circumscribed by R. C. Rollins (1993), Boechera sparsiflora included six varieties encompassing three sexual diploids and a number of apomictic hybrids. The most distinctive of those elements are recognized here as the separate species B. arcuata, B. atrorubens, B. californica, and B. pauciflora. The narrow circumscription of B. sparsiflora adopted here includes only sexual diploids. It is distinguished from other taxa previously assigned to it by having proximal stems densely pubescent with predominantly simple (some 2-rayed) trichomes to 1.5 mm, usually glabrous distal stems, and ascending fruiting pedicels with spreading, usually simple trichomes (rarely glabrous).

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

Source FNA vol. 7, p. 366. FNA vol. 7, p. 407.
Parent taxa Brassicaceae > tribe Boechereae > Boechera Brassicaceae > tribe Boechereae > Boechera
Sibling taxa
B. acutina, B. arcuata, 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. 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. 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. 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 atrorubens, Arabis atriflora, Arabis sparsiflora var. atrorubens Arabis sparsiflora, Arabis arcoidea, Arabis campyloloba, Arabis peramoena, Arabis polytricha, Arabis sparsiflora var. peramoena
Name authority (Suksdorf ex Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 64. (2006) (Nuttall) Dorn: Vasc. Pl. Wyoming ed. 3, 376. (2001)
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