Flora of North America species comparison

In Texas, Lupinus concinnus is known from the trans-Pecos region; in California it is more common in the central and southern areas.

Lupinus concinnus is a highly variable, predominantly self-pollinated complex and the named varieties cannot be consistently segregated. Desert plants with linear, coarsely hairy leaflets and few, minute cilia on lower keel margins (at times recognized as var. desertorum) may be confused with L. sparsiflorus.

(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.)