Flora of North America species comparison

Lupinus antoninus is known only from the type locality on the southwestern slope of Anthony Peak in Mendocino County. The habit and pubescence resemble those of L. adsurgens, but the larger white flowers, the large seeds, and thick stems differentiate it morphologically. According to M. Conrad (1980), it also has different alkaloids. This taxon has not been seen since 1995 and may be extirpated.

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

Shorter plants with more basal leaves have been recognized as subsp. gracilis; intermediates between the named varieties are abundant. Variety occidentalis was described from Michigan and Wisconsin as differing by its dense pubescence, which is a variable trait.

In the northern part of its range, Lupinus perennis is sympatric with L. polyphyllus and can be differentiated because the latter has more leaflets and a glabrous keel. Lupinus perennis is of conservation concern in some states and is an important host plant for lepidopterans; the federally endangered Karner Blue butterfly relies on L. perennis as a larval host plant and sundial lupine also is a larval host plant for Frosted Elfin (Callophrys irus) and Wild Indigo Duskywing (Erynnis baptisiae) butterflies and several species of moths.

Lupinus perennis is toxic and potentially fatal to livestock, due to the alkaloid D-lupaine (M. Wink et al. 1995).

Lupinus gracilis Nuttall (1834, not Kunth 1824) is an illegitimate name that pertains here.

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