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coastal bush lupine, tree lupine, yellow bush lupine

Lupinus pusillus

intermountain lupine, low lupine, rusty lupine

Habit Shrubs, usually 5–20 dm, green-glabrous or silver-hairy. Herbs, annual, 0.5–2 dm, sparsely pubescent to pilose, hairs more than 1 mm.
Stems

ascending or erect, branched, woody.

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

Leaves

cauline;

stipules 8–12 mm;

petiole 2–3(–6) cm;

leaflets 5–12, blades 20–60 × 3–10 mm, adaxial surface glabrous.

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

10–30 cm;

flowers whorled or not.

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

flowers spirally arranged.

Peduncles

4–10 cm;

bracts deciduous, 8–10 mm.

0–3.5 cm;

bracts persistent, straight, 2–5 mm.

Pedicels

4–10 mm.

1–3.5 mm.

Flowers

14–18 mm;

calyx bulge or spur 0–1 mm, abaxial lobe entire, 5–7 mm, adaxial lobe 2-toothed, 5–9 mm;

corolla usually yellow, rarely lilac to purple, banner patch darker or not or white, banner glabrous abaxially, lower keel margins glabrous, adaxial margin ciliate from claw to tip.

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

4–7 cm, hairy.

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

Cotyledons

deciduous, petiolate.

persistent, disclike, sessile.

Seeds

8–12, black to tan, often striped lighter, 4–5 mm.

2, wrinkled or ridged.

2n

= 48.

Lupinus arboreus

Lupinus pusillus

Phenology Flowering Apr–Jul.
Habitat Coastal bluffs, dunes, disturbed sand.
Elevation 0–100 m. (0–300 ft.)
Distribution
from FNA
CA; OR; WA; BC; Mexico (Baja California) [Introduced in South America (Argentina, Chile), Europe, Pacific Islands (New Zealand), Australia (including Tasmania)]
[WildflowerSearch map]
[BONAP county map]
from USDA
w North America; c North America
[WildflowerSearch map]
[BONAP county map]
Discussion

Lupinus arboreus is known from the central California coast southward to northern Baja California; it was introduced as a sand binder and has become naturalized in northern California, Oregon, Washington, and southern British Columbia.

Lupinus arboreus grades into L. rivularis in the North Coast of California. Plants with yellow petals and sweet-smelling flowers are widely cultivated as a sand binder. Hairier plants from the western San Francisco Bay area with yellow banners and blue wings have been called var. eximius; plants with glabrous leaflets and purple petals have been called L. propinquus. Lupinus arboreus hybridizes with L. littoralis and probably other species. Seeds of L. arboreus species are toxic.

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

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 Fabaceae > subfam. Faboideae > Lupinus
Sibling taxa
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, 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
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. arboreus var. eximius, L. propinquus
Name authority Sims: Bot. Mag. 18: plate 682. (1803) Pursh: Fl. Amer. Sept. 2: 468. 1814[1813]
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