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sicklepod, sicklepod rockcress

Peirson's rockcress, San Bernardino Rock cress

Habit Biennials; short-lived; sexual; caudex not evident. Perennials; long-lived; (cespitose); apomictic; caudex woody.
Stems

1 per plant, arising from center of rosette near ground surface, 2.5–10(–12.5) dm, sparsely to densely pubescent proximally, trichomes simple, to 1 mm, glabrous or sparsely pubescent distally.

usually 1 per caudex branch, arising from center of rosette near ground surface, 1–2.5 dm, glabrous or sparsely pubescent proximally, trichomes short-stalked, 2–5-rayed (rarely, some simple), 0.4–0.6 mm, glabrous distally.

Basal leaves

blade obovate to oblanceolate, 10–30 mm wide, margins dentate, ciliate proximally, trichomes simple, to 1 mm, surfaces moderately pubescent, trichomes simple, 0.5–1.5 mm, these mixed with smaller, 2- or 3-rayed ones.

blade oblanceolate, 2.5–6 mm wide, margins entire, ciliate proximally, trichomes (simple), surfaces densely pubescent, trichomes short-stalked, 4–7-rayed, 0.3–0.5 mm.

Cauline leaves

12–20, often concealing stem proximally;

blade auricles absent or proximalmost blades with auricles 0.5–2(–5) mm, surfaces of distalmost leaves sparsely pubescent.

3–12, often concealing stem proximally;

blade auricles 0.5–2 mm, surfaces of distalmost leaves usually glabrous, sometimes margins ciliate.

Racemes

15–65(–82)-flowered, sometimes branched.

12–25-flowered, usually unbranched.

Flowers

divaricate-ascending to horizontal at anthesis;

sepals pubescent;

petals white, 3–5 × 0.7–1.2 mm, glabrous;

pollen ellipsoid.

ascending at anthesis;

sepals pubescent;

petals purple, 5–6 × 1.5–2 mm, glabrous;

pollen spheroid.

Fruiting pedicels

descending to horizontal, usually curved, rarely straight, 6–13(–17) mm, pubescent or glabrous, trichomes subappressed, usually 2-rayed.

ascending to divaricate-descending, straight, 2–6 mm, glabrous.

Fruits

pendent to horizontal, not appressed to rachis, often secund, curved, edges parallel, 4–10 cm × 2.5–4 mm;

valves glabrous;

ovules 40–62 per ovary;

style 0.3–0.8(–1.1) mm.

ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 2–3.7 cm × 2–2.8 mm;

valves glabrous;

ovules 56–80 per ovary;

style 0.1–0.3 mm.

Seeds

uniseriate, 1.7–3.5 × 1.5–2.2 mm;

wing continuous, 0.4–1 mm wide distally.

uniseriate, 1–1.5 × 0.8–1 mm;

wing distal or continuous, 0.05–0.1 mm wide.

2n

= 14.

Boechera canadensis

Boechera peirsonii

Phenology Flowering Apr–Jul. Flowering Jun–Sep.
Habitat Bluffs, rocky slopes, ravines, open woods Granitic ledges and talus slopes
Elevation 0-1200 m (0-3900 ft) 2700-3400 m (8900-11200 ft)
Distribution
from FNA
AL; AR; CT; DC; FL; GA; IA; IL; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NY; OH; OK; PA; TN; TX; VA; VT; WI; WV; QC
[WildflowerSearch map]
from FNA
CA
[BONAP county map]
Discussion

Boechera peirsonii is an apomictic species of unknown origin; although previously treated as a variety of Arabis (B.) breweri, it is quite distinct from that taxon (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). All known collections come from the San Bernardino Mountains of southern California, ca. 200 km distant from the nearest populations of B. breweri.

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

Source FNA vol. 7, p. 369. FNA vol. 7, p. 394.
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. 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. 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 canadensis, Arabis falcata, Arabis hirsuta var. ovata, Arabis ovata Arabis breweri var. pecuniaria
Name authority (Linnaeus) Al-Shehbaz: Novon 13: 384. (2003) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 270. (2007)
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