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

littleleaf suncress, Macoun's suncress, sloppy suncress

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

1 or several per caudex branch, arising from center or margin of rosette near ground surface, 2–3.6 dm, densely pubescent proximally, trichomes simple and short-stalked, 2-rayed, 0.1–0.8 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 oblanceolate to linear-oblanceolate, 1–3(–5) mm wide, margins entire or minutely toothed, ciliate proximally, trichomes (simple), to 0.7 mm, surfaces densely pubescent, trichomes short-stalked, 3–6-rayed, 0.07–0.3 mm.

Cauline leaves

2–6, rarely concealing stem;

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

(5–)9–16, often concealing stem proximally;

blade auricles 0.5–1.5 mm, surfaces of distalmost leaves glabrous.

Racemes

3–8-flowered, unbranched.

10–33-flowered, usually unbranched.

Flowers

erect at anthesis;

sepals glabrous or sparsely pubescent;

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

pollen ellipsoid.

divaricate-ascending at anthesis;

sepals pubescent;

petals lavender to purple, 4–5 × 0.5–0.8 mm, glabrous;

pollen spheroid.

Fruiting pedicels

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

divaricate-ascending to horizontal, straight, 5–13(–17) mm, usually densely pubescent, rarely glabrous, trichomes appressed, 2- or 3-rayed.

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.

divaricate-ascending to descending, not appressed to rachis, not secund, usually curved, edges parallel, 3.5–6.5 cm × 0.8–1.2 mm;

valves glabrous;

ovules 56–78 per ovary;

style 0.1–0.4 mm.

Seeds

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

wing continuous, 0.3–1 mm wide.

uniseriate, 1–1.2 × 0.7–1 mm;

wing often continuous, 0.05–0.15 mm wide.

Boechera paupercula

Boechera macounii

Phenology Flowering Jun–Aug. Flowering May–Jul.
Habitat Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats Rocky hillsides in open pinewoods
Elevation 2400-3400 m (7900-11200 ft) 2200-2900 m (7200-9500 ft)
Distribution
from FNA
CA; ID; OR; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; WY; BC
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.)

Morphological evidence suggests that Boechera macounii is an apomictic species that arose through hybridization between B. collinsii and B. microphylla (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison).

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

Source FNA vol. 7, p. 394. FNA vol. 7, p. 389.
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. 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. 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 macounii, Arabis densicaulis, Arabis microphylla var. macounii
Name authority (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) (S. Watson) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 267. (2007)
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