Prairie lupine is a small, attractive perennial lupine of diverse form and habitats in the Pacific Northwest. It ranges from matted forms to erect plants ranging from 10-35 cm high. The stems are fairly short and often shorter than the tallest leaves. If the stems extend beyond the leaves, then the stem is often prostrate or spreading. The leaves are mostly basal with the petiole 2-5 times longer than the blades. The palmately compound leaves have 5-9 oblanceolate leaflets. The individual leaflets range from 1-4 cm long and are noticeably hairy on both surfaces.
The inflorescence is a tight raceme of crowded flowers. the raceme ranges from 4-15 cm in length. individual flowers are 8-13 mm long and mostly of a bluish color with a lighter banner. The banner is well reflexed from the keel and is not haired on its surfaces. The upper lip of the calyx is double-toothed. The hairy pods range from 10-20 mm long with 2-4 seeds.
Variety aridus: Racemes partially concealed by the longer leaves. Flowers 9-11 mm long. Found from south-central Washington to norhtern California (entirely east of the Cascades) and east to west-central Idaho and Nevada.
Variety cusickii: Racemes mostly concealed by the leaves. Wing petals are broader than 4 mm and usually over 8 mm long. The banner is usually wider than 3/5 of its length. Found from the Blue Mts. of northeastern Oregon and in Okanogan County in Washington.
Variety lepidus: Racemes are well extend above the longest leaves. Flowers 11-13 mm long. Found in the lowlands west of the Cascades from southern British Columbia to northwestern Oregon.
Variety lobbii: Racemes are less than 5 cm long and extend beyond the tallest leaves. Leaflets usually less than 15 mm long. Plants prostrate and matted. Subalpine plants of the Cascade and Olympic Mts. and also found east to western Idaho and Nevada.
Variety utahensis: Racemes mostly concealed by the longer leaves. Wing petalsslender, usually less than 3 mm wide and from 7-8 mm long. The banner is usually less than 3/5 as wide as it is long. Plants found from central Oregon through central Idaho and southeastern Oregon to western Montana and Wyoming and hence south to Colorado and Utah.
Prairie lupine may be found in on gravelly to sandy soils in more arid climates.
Prairie lupine is found from British Columbia south on both sides of the Cascade Mts. to California and east to Montana, Wyoming and Colorado.
It may be found in the Columbia River Gorge between the elevations of 100' to 2200' between Catherine Creek and Horsethief Butte.
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