COCKLEBUR, the name given in the United States to various species of X anthiurn, of the family Compositae, called also clotbur and bur-weed, which in agricultural districts are p e r n i c i o u s weeds. They are coarse, rough and sometimes spiny annual herbs with much branched stems, 1 ft. to 6 ft. high, and mostly long-stalked, variously lobed leaves. The staminate (male) and pistillate (female) flowers, both small and inconspic uous, are borne on separate plants, the staminate clustered at the ends of branches and the pistil late in the axils of the leaves. The fruit (achene) is enclosed in an oblong bur, about an inch in length, covered with hooked spines and ending in a 1- or 2toothed beak. The ripe burs read ily adhere to the hair of farm animals who widely disseminate the plant. When abundant cockleburs are injurious to crops and exhaustive to the soil, but may be controlled by intensive cultivation and by rigorously cutting back or destroying the plants to prevent fruiting in waste grounds.