Lupinus arboreus
Lupinus diffusus
coastal bush lupine, tree lupine, yellow bush lupine
Oak Ridge lupine, skyblue lupine
ascending or erect, branched, woody.
decumbent, spreading, many branched.
cauline;
stipules 8–12 mm;
petiole 2–3(–6) cm;
leaflets 5–12, blades 20–60 × 3–10 mm, adaxial surface glabrous.
basal, clustered;
stipules 20–150 mm;
petiole 2.5–10 cm;
leaflet 1, blades 40–120 × 18–33 mm, adaxial surface densely sericeous or strigulose.
10–30 cm;
flowers whorled or not.
8–30 cm;
flowers whorled.
4–10 cm;
bracts deciduous, 8–10 mm.
3–4 cm;
bracts deciduous, 4–8 mm.
4–10 mm.
1–4 mm.
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.
11–15 mm;
calyx abaxial lobe entire, 5–10 mm, adaxial lobe 3-fid with 2 linear laterals, 4–8 mm;
corolla light to deep blue, limb centrally white at base, banner spot white to cream, glabrous abaxially, keel glabrous.
4–7 cm, hairy.
3–5 cm, appressed villous to sericeous.
deciduous, petiolate.
deciduous, petiolate.
8–12, black to tan, often striped lighter, 4–5 mm.
4–7, gray mottled black, 4 mm.
= 48.
Lupinus arboreus
Lupinus diffusus
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.)
Lupinus diffusus differs from the other unifoliolate species in its much shorter pubescence and banners with a white eyespot. Lupinus cumulicola represents peninsular Florida forms that have strongly ascending foliose stems and sometimes broader leaves than usual. Some plants of L. diffusus from southern Florida have a vesture of hairs that approach those of L. villosus in length.
Lupinus diffusus seeds are known to be toxic (D. J. Wagstaff 2008).
(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
