Lupinus arbustus
Lupinus arboreus
grassland lupine (ssp. neolaxiflorus), long-spur lupine, Montana lupine (ssp. pseudoparviflorus), spur lupine
coastal bush lupine, tree lupine, yellow bush lupine
erect, ascending, or decumbent, branched.
ascending or erect, branched, woody.
cauline and basal;
stipules 4–9 mm;
petiole 2–16 cm;
leaflets 7–10(–13), blades 20–70 × 3–15 mm, adaxial surface strigose.
cauline;
stipules 8–12 mm;
petiole 2–3(–6) cm;
leaflets 5–12, blades 20–60 × 3–10 mm, adaxial surface glabrous.
open, 3–18 cm;
flowers whorled.
10–30 cm;
flowers whorled or not.
2–5 cm;
bracts deciduous, 3–6 mm.
4–10 cm;
bracts deciduous, 8–10 mm.
1–7 mm.
4–10 mm.
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.
14–18 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.
2–3 cm, silky.
4–7 cm, hairy.
deciduous, petiolate.
deciduous, petiolate.
3–6, tan, 5–6 mm.
8–12, black to tan, often striped lighter, 4–5 mm.
= 48.
Lupinus arbustus
Lupinus arboreus
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.)
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.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog.
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
