An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

PINGUE, Colorado rubberweed

Illustration

SUNFLOWER FAMILY-Compositae

PINGUE-Hymenoxys richardsoni (Hook.) Cockl. var. floribunda (Gray) Parker

DESCRIPTION-Low, tufted, upright perennial, from a branched woody root crown, with long cottony hairs in the old leaf bases, reproducing by seeds only. The plants are bitter tasting, with a strong pungent odor. The several stems are greatly branched above, and 6 to 18 inches high.

The fleshy leaves, with the surface gland dotted, are rather rigid. They form basal tufts around the stems, are 1 1/2 to 6 inches long, with a dense mass of cottony hairs between the axils. The leaves on the stem are alternate, 3/4 to 2 inches long. All are very narrow, and may be undivided or mostly divided into 3 to 7 long narrow lobes, about 1/25 to 1/12 inch broad.

The yellow sunflowerlike heads are 1/2 to 1 1/4 inch across, including the 7 to 10 bright yellow marginal or ray flowers, and the tiny, tubular central flowers. The ray flowers are persistent and become whitish and pendent in age. The heads occur in large numbers at the tips of all the branches, giving the plant a flattopped appearance. Each head produces many achenes similar to those of bitter rubberweed, but about 1/8 inch long.

DISTRIBUTION-A native perennial weed, thriving on all soils from dry to moist, poor to fertile, and sandy to heavy clays. Pingue reaches its greatest development in open grasslands, occupying all slopes and exposures with nearly equal vigor and density. It grows well, although stands may be sparce under oak, juniper, and ponderosa pine. A serious and abundant weed on northeastern Arizona ranges, from Apache to Coconino and Yavapai counties; 5,000 to 9,000 feet elevation; flowering from late June to September.

Pingue increases in abundance whenever the grass cover is thinned by continued close grazing. The plant contains a high percentage of latex, which was extracted during both World War I and II, and manufactured into rubber. High costs of harvesting and latex extraction, and slow growth of the plant prevent commercial development.

POISONOUS PROPERTIES-Pingue is poisonous to sheep. The plant is not eaten by cattle. Death losses in sheep may occur at any time of the year, but the greatest danger is in the spring or late fall when palatable forage is apt to be scarce, and sheep are forced to eat pingue.

Copyright (c) 1972 The Arizona Board of Regents



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