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intermontane lupine, intermountain lupine, low lupine, rusty lupine

Lupinus pusillus

intermountain lupine, low lupine, rusty lupine

Habit Herbs, annual, 0.5–2 dm, sparsely pubescent to pilose, hairs more than 1 mm.
Stems

short and tufted or erect, branched from base or near middle.

Leaves

cauline, often crowded near base;

stipules well developed;

petiole 1–9 cm;

leaflets 5–9, blades 10–40 × 5–10 mm, adaxial surface glabrous.

Racemes

2–5 cm, usually shorter than foliage.

8–12-flowered, 2–11 cm, shorter than or slightly exceeding foliage;

flowers spirally arranged.

Peduncles

0–1 cm.

0–3.5 cm;

bracts persistent, straight, 2–5 mm.

Pedicels

strigose.

1–3.5 mm.

Flowers

6–8 mm;

calyx tube strigose.

5–12 mm;

calyx abaxial lobe entire, 5–6 mm, adaxial lobe cleft, 2.5–4 mm;

corolla vivid blue, sometimes paler or white, sometimes bicolored, banner spot white or yellowish, keel glabrous.

Legumes

1.5 cm, constricted between seeds, thinly pilose to coarsely hirsute.

Cotyledons

persistent, disclike, sessile.

Seeds

2, wrinkled or ridged.

Lupinus pusillus var. intermontanus

Lupinus pusillus

Phenology Flowering spring—early summer.
Habitat Open sandy areas.
Elevation 1100–1800 m. (3600–5900 ft.)
Distribution
from FNA
CA; ID; NV; OR; WA; WY
[BONAP county map]
from USDA
w North America; c North America
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

Lupinus pusillus is a highly variable species, with the varieties intergrading.

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

Key
1. Peduncles 0–1 cm; racemes shorter than foliage; flowers 6–8 mm.
var. intermontanus
1. Peduncles usually 1–3.5 cm; racemes equal to or longer than foliage; flowers 7–12 mm.
→ 2
2. Pedicels and calyx tubes strigose.
var. pusillus
2. Pedicels and calyx tubes glabrous.
var. rubens
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Lupinus > Lupinus pusillus Fabaceae > subfam. Faboideae > Lupinus
Sibling taxa
L. pusillus var. pusillus, L. pusillus var. rubens
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, L. arboreus, L. arbustus, 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. 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
Subordinate taxa
L. pusillus var. intermontanus, L. pusillus var. pusillus, L. pusillus var. rubens
Synonyms L. intermontanus, L. pusillus var. intermontanus, L. pusillus subsp. intermontanus
Name authority (A. Heller) C. P. Smith: Bull. Torrey Bot. Club 46: 408. (1919) Pursh: Fl. Amer. Sept. 2: 468. 1814[1813]
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