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Lupinus pusillus

intermountain lupine, low lupine, rusty lupine

naked lupine, summit lupine

Habit Herbs, annual, 0.5–2 dm, sparsely pubescent to pilose, hairs more than 1 mm. Herbs, perennial, 2–6 dm, green, puberulent to sparsely appressed-hairy.
Stems

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

erect, branched.

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.

cauline;

stipules 5–10 mm;

petiole 2–5 cm;

leaflets 7–9, blades 25–55 × 4–12 mm, adaxial surface pubescent.

Racemes

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

flowers spirally arranged.

8–11 cm;

flowers spirally arranged to whorled.

Peduncles

0–3.5 cm;

bracts persistent, straight, 2–5 mm.

1–8 cm;

bracts deciduous, 3.5–5 mm.

Pedicels

1–3.5 mm.

3–6 mm.

Flowers

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.

10–12 mm;

calyx bulge or spur 0–1 mm, abaxial lobe entire or 3-toothed, 4.5–7 mm, adaxial lobe 2-toothed, 3.5–6 mm;

corolla usually purple, sometimes pink or white, banner patch usually white, banner hairy abaxially, keel glabrous.

Legumes

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

2–3 cm, hairy.

Cotyledons

persistent, disclike, sessile.

deciduous, petiolate.

Seeds

2, wrinkled or ridged.

3 or 4, 5–6 mm.

Lupinus pusillus

Lupinus apertus

Phenology Flowering Jun–Jul.
Habitat Dry, rocky soils.
Elevation 1500–3000 m. [4900–9800 ft.]
Distribution
map from USDA
w North America; c North America
[WildflowerSearch map]
[BONAP county map]
map from FNA
CA; NV
[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.)

Lupinus apertus is found in the northern High Sierra Nevada from Plumas to El Dorado counties in California and eastward to southwestern Washoe County, Nevada.

Lupinus apertus can be differentiated from L. andersonii by its abaxial banner pubescence and from L. angustiflorus by its pale yellow to orange-yellow flowers. Lupinus apertus is reportedly toxic.

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

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. 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
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, 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. 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
Subordinate taxa
L. pusillus var. intermontanus, L. pusillus var. pusillus, L. pusillus var. rubens
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
Synonyms L. andersonii var. apertus
Name authority Pursh: Fl. Amer. Sept. 2: 468. 1814[1813] A. Heller: Muhlenbergia 8: 103, fig. 15. (1912)
Source FNA vol. 11. Treatment authors: Teresa Sholars, Rhonda Riggins. FNA vol. 11. Treatment authors: Teresa Sholars, Rhonda Riggins.
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