Lupinus argenteus var. argenteus “Silvery Lupine” Fabaceae
Lolo National Forest, Bitterroot Mountains, MT
May 10, 2015
Robert Niese
Our two most common Lupines in the Missoula area are the Silvery and Silky Lupines (L. argenteus and L. sericeus, respectively). You can easily tell them apart by the upper petals on their flowers (called the “banner” in papilionaceous pea flowers). In the Silvery Lupine (pictured here), the backside of the banner has no hairs, while the Silky Lupine has a dense coating of hair on its banners. In our area, Silvery Lupines that grow in the dry soils of Ponderosa Pinelands and have folded leaflets are of the var. argenteus.
Northwest Naturalist 