This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Herbs, rarely shrubs, with alternate digitately-compound 7-15-foliolate (rarely simple or 3-5-foliolate) leaves, and showy flowers in terminal spikes or racemes. Calyx deeply toothed and 2-lipped. Standard orbicular or ovate, its margins reflexed; wings oblong or obovate; keel incurved, sometimes beaked. Stamens monadelphous, their sheath not cleft; anthers of two forms as in Crotalaria. Ovary sessile; style incurved. Pod flattened, generally constricted between the seeds, the valves coriaceous. [Latin name of some pulse, from lupus, wolf.]
Over 100 species, mainly natives of temperate and warm regions. About 70 occur in North America, mainly on the western side of the continent. Type species: Lupinus albus L.
Perennial; flowers 7"-9" long; leaflets oblanceolate.
Corolla blue, with a conspicuous dark spot on the standard.
Perennial; flowers 4"-6" long; leaflets oblong-linear.
Annual; leaflets mainly oblong; pod 2-seeded.
Perennial, erect, more or less pubescent, sometimes villous, branched, 1°-2° high. Leaves slender-petioled, 2'-3' broad, leaflets 7-11 (commonly about 8), oblan-ceolate, sessile or nearly so, obtuse and mucronate at the apex, 1'-1 1/2' long, 3"-6" wide, appressed-pubescent or glabrate; raceme terminal, peduncled, 6'-10' long, rather loosely flowered; pedicels 3"-6" long; flowers blue, sometimes pink, or white, 6"-8" long; pod linear-oblong, very pubescent, 11/2' long, 4" wide, usually 4-6-seeded, the valves coiling at dehiscence; style subulate.
Lupinus omatus var. glabratus S. Wats.
Proc. Am. Acad. 8: 528. 1873. Not L.
glabratus Agardh. 1835. Lupinus plattensis S. Wats. Proc. Am.
Acad. 17: 369. 1882.
Resembling the preceding species, perennial, 1°- 1 1/2° high, branching, villous or appressed-pubescent, the living plant with a glaucous appearance; leaflets 7-10, oblanceolate, spatulate or narrowly oval,1'-1 1/2' long, 3"-5" wide; raceme terminal, 4's' long, loosely flowered; pedicels 3"-5" long; corolla blue, 6"-8" long, the standard with a conspicuous dark spot.
Plains, Nebraska, Wyoming, Colorado. Recorded from Dakota. June-July.
Lupinus decumbens Torr. Ann. Lyc. N. Y. 2: 191. 1826.
Perennial, rather shrubby, bushy-branched, 1°-2° high, finely and densely silky-pubescent with appressed hairs, the leaves becoming glabrous on the upper side. Petioles slender, equalling or the lower exceeding the leaves; stipules minute, subulate; leaflets sessile, linear-oblong, acute or obtusish at the apex, narrowed at the base, 9"-18" long, 2"-4" wide; racemes terminal, rather dense, 2'-8' long; pedicels 2" - 3" long; flowers purple, 4"-6" long; pod silky-pubescent, about 1' long, mostly 3-5-seeded.
Lupinus argophyllus (A. Gray) Cockerell, of Colorado and New Mexico, differing in having leaves permanently pubescent above, is recorded from Nebraska.
Lupinus pusillus Pursh, Fl. Am. Sept. 468. 1814.
Annual (always?), villous-pubescent, 4'-8' high, from a deep root, much branched near the base. Leaves petioled, 1'-2' wide; leaflets 5-7 (commonly 5), oblong or oblanceolate, narrowed at the base, obtuse or acute at the apex, glabrous or nearly so on the upper surface, pubescent with long scattered hairs beneath, 3"-4" wide; racemes numerous, short-peduncled or sessile, 1'-3' long, densely few-flowered; pedicels 1"-2" long; flowers blue, 3"-4" long; pod oblong, very pubescent, 6"-8" long, 2"-3' broad, about 2-seeded; style subulate.
Dry plains, South Dakota to Nebraska, Kansas, Montana, Oregon, Washington, Nevada and New Mexico. March-July.