An Illustrated Guide to ARIZONA WEEDS
The University of Arizona Press
HALOGETON-Halogeton glomeratus (M. Bieb.) C. A. Mey
DESCRIPTION-Halogeton is not known to occur in Arizona at this writing, but doubtless it is only a matter of time, since it is common along the border both in Nevada and Utah. It is a fleshy annual, 2 inches to 2 feet high, branching from the base, and closely resembles young Russian thistle. The mature leaves of halogeton are soft, and end in a white hairlike bristle instead of a rigid spine. Also there are tufts of kinky whitish hairs in the leaf axils, which are not present in Russian thistle.
The 5 dry flower parts enlarge, and at maturity form showy yellowish to reddish fanlike wings. The flower parts are usually thought of as the fruits, but they actually enclose the tiny fruit with its 1 seed. These flower parts are about 1/4 inch across, and may be so abundant in the fall as to hide the stems and leaves. The tiny seed, like that of Russian thistle, shows the coiled embryo.
DISTRIBUTION-Halogeton is a weed of the dry deserts, on barren eroded soil of overgrazed ranges, road shoulders, or any disturbed site; flowering and fruiting July to October with fruits persistent. A native of Russia, it was introduced into the United States in about 1930, and apparently was first identified in Nevada in 1934. It now covers millions of acres in Nevada, Utah, and Idaho, and is found also in Montana, Wyoming, Oregon, and California.
POISONOUS PROPERTIES-Mature halogeton plants contain high concentrations of soluble oxalic acid salts, and are extremely toxic. Sheep are poisoned more often than cattle under usual conditions. A lethal dose for sheep is about 1 1/2 pounds of green plant. Poisoning usually occurs in late fall or early winter, since snow or rain washes out the poison. The poison is not cumulative; a toxic dose must be eaten at one time. The animal becomes dull and cannot move 2 to 4 hours after eating a lethal dose; death may follow within 6 to 10 hours.
Copyright (c) 1972 The Arizona Board of Regents