The principal uses for which these plants are employed in medicine are briefly indicated, but none of the drugs mentioned should be taken without the advice of a physician. With the exception of the figures for dandelion and mustard, which were obtained from the Bureau of Statistics of the Department of Commerce and Labor, the imports are based on estimates furnished by dealers, and the prices per pound, while serving to give an idea as to what may be expected for the drugs, will vary from year to year, depending principally upon supply and demand. There are of course a large number of plants used in medicine that are not included in this bulletin, which is intended to cover only such medicinal plants as may be classed as weeds. BURDOCK. _Arctium lappa_ L. =Other common names.=—Cockle button, cuckold dock, beggars’ buttons, hurr-bur, stick button, hardock, and bardane. (Fig. 1.) [Illustration: FIG. 1.—Burdock (_Arctium lappa_ L.). Flowering plant.] =Habitat and range.=—Burdock is one of the most common weeds. It was introduced from the Old World, and is common and often very abundant in the Eastern and Central States and in some scattered localities in the West, growing along roadsides, in fields, pastures, and waste places. =Description.=—This is a coarse, unsightly biennial weed of the aster family (Asteraceæ), which produces during the first year of its growth only a rosette of large, thin leaves (fig. 2) and a long, tapering root having a diameter of from one-half to 1 inch. When full grown it measures from 3 to 7 feet high. The round, fleshy stem is branched, grooved, and hairy, with very large leaves, even in the early stages of the growth of the plant, the lower leaves often measuring 18 inches in length. The leaves are alternate, on long, solid, deeply furrowed leafstalks; thin, roundish or oval, but usually heart-shaped; with even, wavy, or toothed margins; smooth above, and pale and woolly on the under surface. The flowers are purple, in small, clustered heads, appearing in the second year, from July to frost. These flower heads are armed with hooked tips, and the burs thus formed are a great pest, attaching themselves to clothing and to the wool and hair of animals. The seed of burdock is produced in great abundance, one plant bearing as many as 400,000 seeds. =Parts used.=—The root alone is recognized in the United States Pharmacopœia, but there is a limited demand for burdock seed, and the leaves also are employed. Burdock roots and seeds are used in blood and skin diseases, and the leaves externally as a cooling poultice for swellings and ulcers, the latter being employed only in the fresh state. [Illustration: FIG. 2.—Burdock. First year’s growth.]