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Lupinus pusillus

intermountain lupine, low lupine, rusty lupine

Cobb Mountain lupine

Habit Herbs, annual, 0.5–2 dm, sparsely pubescent to pilose, hairs more than 1 mm. Herbs, perennial, 1.5–5 dm, silver to gray-green, short-appressed-hairy.
Stems

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

erect, ascending, or decumbent, 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, clustered near base;

stipules 2–7 mm;

petiole 5–15 cm;

leaflets 4–7, blades widely spoon-shaped, 30–40(–50) × 10–20 mm, surfaces densely silky.

Racemes

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

flowers spirally arranged.

open to dense, 10–30 cm;

flowers ± whorled.

Peduncles

0–3.5 cm;

bracts persistent, straight, 2–5 mm.

8–15 cm;

bracts deciduous, 3–4 mm.

Pedicels

1–3.5 mm.

4–6 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.

12–16 mm;

calyx bulge or spur 0–1 mm, abaxial lobe 3-toothed, 7–10 mm, adaxial lobe 2-toothed, 6–10 mm;

corolla purple to violet, banner ± hairy abaxially, lower keel margins usually ± glabrous, adaxial margin ciliate claw to tip.

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.

3–7, light brown, 3–5 mm.

Lupinus pusillus

Lupinus sericatus

Phenology Flowering Mar–Jun.
Habitat Open wooded slopes.
Elevation 200–1600 m. (700–5200 ft.)
Distribution
from USDA
w North America; c North America
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[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 sericatus is known from the southern Inner North Coast Ranges in Colusa, Lake, Napa, and Sonoma counties.

(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 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. 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. pusillus, L. rivularis, L. sabineanus, 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
Name authority Pursh: Fl. Amer. Sept. 2: 468. 1814[1813] Kellogg: Proc. Calif. Acad. Sci. 7: 92. (1877)
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