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Lupinus arbustus

grassland lupine (ssp. neolaxiflorus), long-spur lupine, Montana lupine (ssp. pseudoparviflorus), spur lupine

arctic lupine

Habit Herbs, perennial, 2–7 dm, green or gray-silky. Herbs, perennial, 1–4 dm, hairs thinly appressed silky-sericeous, or few to many and spreading; caudex superficial, divisions closely tufted.
Stems

erect, ascending, or decumbent, branched.

ascending to erect, hollow, tufted, branched at crown.

Leaves

cauline and basal;

stipules 4–9 mm;

petiole 2–16 cm;

leaflets 7–10(–13), blades 20–70 × 3–15 mm, adaxial surface strigose.

mostly basal with a few cauline proximal to inflorescences;

stipules 8–10 mm;

petiole 5–19 cm;

leaflets 6–10, blades 13–90 × 10–15 mm, abaxial surface thinly strigose, adaxial surface glabrous.

Racemes

open, 3–18 cm;

flowers whorled.

5–8(–15 in fruit) cm;

flowers spirally arranged or in 3–7 whorls.

Peduncles

2–5 cm;

bracts deciduous, 3–6 mm.

4–8.5 cm;

bracts caducous to tardily deciduous, 8–14 mm.

Pedicels

1–7 mm.

4–6 mm.

Flowers

8–14 mm;

calyx spur distinct, 1–3 mm, abaxial lobe 3-toothed, 2.5–5 mm, 1–3 mm, adaxial lobe 2-toothed, 2–4 mm;

corolla blue, purple, pink, white, or yellowish, banner patch white, yellowish, or absent, banner hairy abaxially, wings with dense hair patch outside near tip, lower keel margins glabrous, adaxial margin ciliate.

14–19(–21) mm;

calyx bulge or spur 0–1 mm, abaxial lobe 6–11 mm, entire or faintly notched at tip, adaxial lobe ± gibbous basally, adaxial lobe teeth with slight notch at tip, 4–8 mm;

corolla usually blue to purplish, sometimes pink, rarely white, banner spot white or yellow, sometimes becoming purple, banner glabrous abaxially, lower keel margins densely ciliate near claw or glabrous or sparsely ciliate towards tip, adaxial margin glabrous or sparsely ciliate towards tips.

Legumes

2–3 cm, silky.

2–4.3 cm, silky-pilose.

Cotyledons

deciduous, petiolate.

deciduous, petiolate.

Seeds

3–6, tan, 5–6 mm.

5–8, mottled.

2n

= 48.

Lupinus arbustus

Lupinus arcticus

Phenology Flowering May–Jul. Flowering Jun–Aug.
Habitat Open sagebrush scrub or mixed-conifer forests. Well-drained hummocks of alpine and arctic tundra, moist to mesic meadows, gravel bars, clearings, roadsides, thickets, open forests.
Elevation 1500–3000 m. (4900–9800 ft.) 0–2000 m. (0–6600 ft.)
Distribution
from FNA
CA; ID; MT; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; BC; NT; NU; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

Lupinus arbustus is known from the Cascade and Klamath ranges, San Gabriel Mountains, Sierra Nevada, and the Great Basin area in California; Owyhee Desert in Idaho and Oregon; eastern Washington and western Montana; and western Juab and Tooele counties, Utah.

Lupinus arbustus is separated from the argenteus group by the presence of hairs on the corolla wings. Recognition of subspecies and varieties of this already complex species leads to precarious separation among taxa.

Lupinus variegatus A. Heller (1912, not Poiret 1814) is an illegitimate name that pertains here.

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

The relationship between Lupinus arcticus and L. latifolius is unclear. They may be distinguished by the presence of proximal keel ciliation in L. latifolius, and basal rather than cauline leaves dominating in L. arcticus.

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

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Lupinus Fabaceae > subfam. Faboideae > Lupinus
Sibling taxa
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, L. arboreus, L. arcticus, L. argenteus, L. arizonicus, L. benthamii, L. bicolor, L. brevicaulis, L. breweri, L. cervinus, L. chamissonis, L. citrinus, L. concinnus, L. constancei, L. covillei, L. croceus, L. dalesiae, L. diffusus, L. duranii, L. elatus, L. elmeri, L. excubitus, L. flavoculatus, L. formosus, L. fulcratus, L. gracilentus, L. grayi, L. guadalupensis, L. havardii, L. hirsutissimus, L. huachucanus, L. hyacinthinus, L. kingii, L. kuschei, L. lapidicola, L. latifolius, L. lepidus, L. leucophyllus, L. littoralis, L. longifolius, L. ludovicianus, L. luteolus, L. magnificus, L. malacophyllus, L. microcarpus, L. nanus, L. neomexicanus, L. nevadensis, L. nipomensis, L. nootkatensis, L. obtusilobus, L. odoratus, L. onustus, L. oreganus, L. pachylobus, L. padrecrowleyi, L. peirsonii, L. perennis, L. polyphyllus, L. pratensis, L. pusillus, L. rivularis, L. sabineanus, L. sericatus, L. sericeus, L. shockleyi, L. sierrae-blancae, L. sparsiflorus, L. spectabilis, L. stiversii, L. subcarnosus, L. succulentus, L. sulphureus, L. texensis, L. tidestromii, L. tracyi, L. truncatus, L. uncialis, L. villosus, L. westianus
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, L. arboreus, L. arbustus, L. argenteus, L. arizonicus, L. benthamii, L. bicolor, L. brevicaulis, L. breweri, L. cervinus, L. chamissonis, L. citrinus, L. concinnus, L. constancei, L. covillei, L. croceus, L. dalesiae, L. diffusus, L. duranii, L. elatus, L. elmeri, L. excubitus, L. flavoculatus, L. formosus, L. fulcratus, L. gracilentus, L. grayi, L. guadalupensis, L. havardii, L. hirsutissimus, L. huachucanus, L. hyacinthinus, L. kingii, L. kuschei, L. lapidicola, L. latifolius, L. lepidus, L. leucophyllus, L. littoralis, L. longifolius, L. ludovicianus, L. luteolus, L. magnificus, L. malacophyllus, L. microcarpus, L. nanus, L. neomexicanus, L. nevadensis, L. nipomensis, L. nootkatensis, L. obtusilobus, L. odoratus, L. onustus, L. oreganus, L. pachylobus, L. padrecrowleyi, L. peirsonii, L. perennis, L. polyphyllus, L. pratensis, L. pusillus, L. rivularis, L. sabineanus, L. sericatus, L. sericeus, L. shockleyi, L. sierrae-blancae, L. sparsiflorus, L. spectabilis, L. stiversii, L. subcarnosus, L. succulentus, L. sulphureus, L. texensis, L. tidestromii, L. tracyi, L. truncatus, L. uncialis, L. villosus, L. westianus
Synonyms L. arbustus subsp. calcaratus, L. arbustus var. montanus, L. arbustus subsp. neolaxiflorus, L. arbustus subsp. pseudoparviflorus, L. arbustus subsp. silvicola, L. caesius, L. caudatus var. submanens, L. caudatus var. subtenellus, L. elegantulus, L. inyoensis var. demissus, L. laxiflorus var. calcaratus, L. laxiflorus var. cognatus, L. laxiflorus var. elmerianus, L. laxiflorus var. lyleianus, L. laxiflorus var. pseudoparviflorus, L. laxiflorus var. silvicola, L. laxiflorus var. villosulus, L. lyleianus, L. mucronulatus var. umatillensis, L. multitinctus, L. noldekeae, L. proteanus, L. pseudoparviflorus, L. silvicola, L. wenatchensis, L. yakimensis L. borealis, L. donnellyensis, L. gakonensis, L. multicaulis, L. multifolius, L. nootkatensis var. kjellmannii, L. polyphyllus subsp. arcticus, L. toklatensis, L. yukonensis
Name authority Douglas: Edwards’s Bot. Reg. 15: plate 1230. (1829) S. Watson: Proc. Amer. Acad. Arts 8: 526. (1873)
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