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boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress

Cascade rock-cress, Cascade suncress, Cascades rockcress, littleleaf rockcress

Habit Perennials; long-lived; (cespitose); sexual; caudex often woody. Perennials; long-lived; (cespitose); apomictic; caudex somewhat woody.
Stems

usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.5 dm, densely pubescent proximally, trichomes simple and short-stalked, 2–4-rayed, (0.07–)0.1–0.2 mm, glabrous or sparsely pubescent distally.

usually 1 per caudex branch, arising from center of rosette near ground surface, 0.5–2.2 dm, sparsely pubescent proximally, trichomes simple and short-stalked, 2- or 3-rayed, 0.1–0.2 mm, glabrous distally.

Basal leaves

blade linear-oblanceolate, 1–3(–5) mm wide, margins entire, ciliate proximally, trichomes to 0.4 mm, surfaces densely pubescent, trichomes short-stalked, 2–6-rayed, (0.07–)0.1–0.2 mm.

blade linear-oblanceolate, 0.7–2 mm wide, margins entire, ciliate proximally, trichomes to 0.4 mm, surfaces densely pubescent, trichomes short-stalked, (2- or) 3–6-rayed, 0.05–0.2(–0.3) mm.

Cauline leaves

2–6, rarely concealing stem;

blade auricles 0 (or 0.2–1.5) mm, surfaces of distalmost leaves glabrous.

4–6, not concealing stem;

blade auricles 0.5–1 mm, surfaces of distalmost leaves glabrous.

Racemes

3–8-flowered, unbranched.

3–11-flowered, unbranched.

Flowers

erect at anthesis;

sepals glabrous or sparsely pubescent;

petals lavender to purplish, 4–6(–7) × 1–2 mm, glabrous;

pollen ellipsoid.

ascending at anthesis;

sepals glabrous or sparsely pubescent;

petals lavender, 5–6 × 1–1.7 mm, glabrous;

pollen spheroid.

Fruiting pedicels

erect, straight, 3–9 mm, glabrous or sparsely pubescent.

ascending to divaricate-ascending, straight, 3–8 mm, glabrous.

Fruits

erect, appressed to rachis, not secund, straight, edges parallel, 2.5–5.5 cm × 1.3–1.7(–2) mm;

valves glabrous;

ovules 24–40 per ovary;

style 0.2–1 mm.

ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 3.5–6.2 cm × 1.2–1.5 mm;

valves glabrous;

ovules 58–80 per ovary;

style 0.8–1.5 mm.

Seeds

usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm;

wing continuous, 0.3–1 mm wide.

uniseriate, 1.1–1.3 × 0.9–1 mm;

wing continuous, 0.05–0.1 mm wide.

Boechera paupercula

Boechera cascadensis

Phenology Flowering Jun–Aug. Flowering Jun.
Habitat Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats Basaltic cliffs and rocky slopes in subalpine areas
Elevation 2400-3400 m (7900-11200 ft) ca. 1900 m (ca. 6200 ft)
Distribution
from FNA
CA; ID; OR; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
OR; WA
[BONAP county map]
Discussion

Boechera paupercula is usually subsumed under Arabis (Boechera) lyallii but is amply distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison).

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

Of conservation concern.

Morphological evidence suggests that Boechera cascadensis is an apomictic species that arose through hybridization between B. microphylla and B. paupercula (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). It is known from two collections: the type specimens from Kittitas County, Washington, and a more recent collection from Baker County, Oregon.

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

Source FNA vol. 7, p. 394. FNA vol. 7, p. 369.
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. 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. 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
Synonyms Arabis paupercula, Arabis lyallii var. nubigena, Arabis microphylla var. nubigena, Arabis nubigena Arabis microphylla var. thompsonii
Name authority (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 260. (2007)
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