The flower parts are usually thought of as the fruits, but they actually enclose the tiny fruit with its 1 seed. The tiny seed, like that of Russian thistle, shows the coiled embryo. 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. Sheep are poisoned more often than cattle under usual conditions.
Poisoning usually occurs in late fall or early winter, since snow or rain washes out the poison.