An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press




DESERT THORNAPPLE-Datura discolor Bernh.

DESCRIPTION-An erect low annual with stout stems branching from the base, 1 to 2 feet high, which reproduces only by seeds. The plants are small and green; the leaf blades, only about 2 to 4 inches long, are slightly rounded.

The flowers are trumpetshaped, white tinged with violet, mostly 2 to 4 inches, rarely to 6 inches long, 2 inches or less across, and the margin has 10 slender teeth rather than 5. The calyx is 2 1/4 inches long, and 5-angled.

The large globeshaped seedpods, 1 to 1 1/2 inches in diameter at maturity, are on thick down curved stalks. The many-seeded pods are covered by stout spines; the longer ones are 3/8 inch long when mature. The seedpods are sticky and short hairy, as are the spines. The ripe seeds are black, about l/8inch long, kidneyshaped, flattened; the surface is finely roughened, pitted, and bordered by a wavy grooved margin.

DISTRIBUTION-Desert thornapple is a native weed; very common in cultivated fields in some areas, as in the Yuma Valley. It is confined to southern Arizona in Cochise, Pima, Pinal, Maricopa, and Yuma counties; mostly 100 to 2,600 feet, sometimes to 4.000 feet elevation; flowering July to November.

POISONOUS PROPERTIES-All parts of the plant of the various species of Datura are poisonous; the seeds are the most toxic, and the young leaves next. They are poisonous to all classes of livestock and to humans. Under normal range conditions, the plants cause little trouble. Animals will not eat them unless forced to do so through starvation or confinement within heavily used pastures or corrals.

Copyright (c) 1972 The Arizona Board of Regents

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