An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press



PEA FAMILY-Leguminosae

KINGS LUPINE-Lupinus kingii Wats.

DESCRIPTION-A low bushy hairy annual 3 to 8 inches high, with long and fine dense hairs. The leaves are alternate, and divided into 5 (sometimes 6 to 9) leaflets which arise from a common point at the end of the short (1/2 to 1 1/2) inches long), hairy leaf stalks.

The small pealike flowers, about l/3 to 1/2 inch long, are blue or violet, with whitish centers. They are crowded very close together on short flower branches only 1/2 to 3/4 or 1 inch long, which rarely extend beyond the leaves. The mature pods are eggshaped, 1/3 to scarcely 1/2 inch long, and contain just 2 seeds. The grayish tan seeds are rounded, plumpish and scarcely l/8 inch in diameter, with the surfaces smooth.

DISTRIBUTION-A very common native weed in rocky clay or disturbed soil along highways, old fields, vacant lots, and waste places. Also locally abundant on eroded or overgrazed meadows and openings in yellow pine, and sometimes in pinyon-juniper ranges, mostly in northern Arizona, from Apache to Coconino and Yavapai counties, rare southward in Graham, Cochise, and Pima counties 5,500 to 8,000 feet elevation; flowering May to September, mostly June to August.

Kings lupine contains poisonous alkaloids, but is not known to be the cause of livestock poisoning.

LOW LUPINE-Lupinus pusillus Pursh

DESCRIPTION-A low annual similar in appearance to kings lupine. Differing in that the flower branches are 1 to 2 1/2 inches long, with the flowers not as crowded; also the pods are oblong, 1/2 to 3/4 inch long, and are indented or con- stricted between the 2 seeds. Low lupine occurs in dry sandy soil of mesas, canyons, and wastelands in northern Arizona, mostly on pinyon-juniper ranges from Apache to Mohave counties; 4,500 to 8,000 feet elevation; flowering May to June.

POISONOUS PROPERTIES OF NATIVE LUPINES-Among the 22 kinds of native lupines in Arizona, 2 are important elsewhere as the serious cause of livestock poisoning, chiefly to sheep. Silvery lupine (L. argenteus Pursh), the most common perennial lupine in the forests of northern Arizona at 7,000 to 10,000 feet elevation, is very serious in most western states, and low lupine (L. pusillus) in Kansas. Lupines may be expected to cause some sheep fatalities in Arizona.

Copyright (c) 1972 The Arizona Board of Regents

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