_Lupinus perennis_
_Flowers_--Vivid blue, very rarely pink or white, butterfly-shaped;
corolla consisting of standard, wings, and keel; about 1/2 in. long,
borne in a long raceme at end of stem; calyx 2-lipped, deeply toothed.
_Stem:_ Erect, branching, leafy, 1 to 2 ft. high. _Leaves:_ Palmate,
compounded of from 7 to 11 (usually 8) leaflets. _Fruit:_ A broad,
flat, very hairy pod, 1-1/2 in. long, and containing 4 or 5 seeds.
_Preferred Habitat_--Dry, sandy places, banks, and hillsides.
_Flowering Season_--May-June.
_Distribution_--United States east of Mississippi, and eastern Canada.
Farmers once thought that this plant preyed upon the fertility of their
soil, as we see in the derivation of its name, from _lupus_, a wolf;
whereas the lupine contents itself with sterile waste land no one should
grudge it--steep, gravelly banks, railroad tracks, exposed sunny hills,
where even it must often burn out under fierce sunshine did not its root
penetrate to surprising depths. It spreads far and wide in thrifty
colonies, reflecting the vivid color of June skies, until, as Thoreau
says, “the earth is blued with it.”
The lupine is another of those interesting plants which go to sleep at
night. Some members of the genus erect one half of the leaf and droop
the other half until it becomes a vertical instead of the horizontal
star it is by day. Frequently the leaflets rotate as much as 90 degrees
on their own axes. Some lupines fold their leaflets, not at night only,
but during the day also there is more or less movement in the leaves.
Sun dial, a popular name for the wild lupine, has reference to this
peculiarity. The leaf of our species shuts downward around its stem
umbrella fashion, or the leaflets are erected to prevent the chilling
which comes to horizontal surfaces by radiation, some scientists think.
“That the sleep movements of leaves are in some manner of high
importance to the plants which exhibit them,” says Darwin, “few will
dispute who have observed how complex they sometimes are.”