Other common names.—Houndsbene, marvel, marrube. (Fig. 21.)
Range and habitat.—Hoarhound has been naturalized from Europe, and has escaped from gardens in this country, being found now rather abundantly in dry sandy or stony soil in waste places, pastures, fields, along roadsides, and near dwellings, from Maine to South Carolina, Texas, and westward to California and Oregon. It is very abundant in pastures in California, Oregon, and in limited areas in Indiana, Missouri, Ohio, and Michigan. In southern California this plant has proved a most troublesome weed, occurring almost everywhere and growing in such dense masses as to crowd out all other vegetation. It has spread rapidly over thousands of acres, taking complete possession of the land and destroying pastures.
Description.—The entire plant has a whitish, woolly appearance, caused by the dense covering of hairs. It is a perennial plant, and as will be seen from the characteristic lip-shaped flowers, is a member of the mint family (Menthaceæ). The whole plant has a rather pleasant, balsamic odor.
Fig. 21.—Hoarhound (Marrubium vulgare L.).
Hoarhound is a bushy, branching herb, with fibrous roots sending up numerous woolly stems about 1 to 3 feet high, rounded below and four-angled above. The leaves are opposite each other, 1 to 2 inches long, oval or nearly round, wrinkled, somewhat blunt at the apex, narrowed or somewhat heart shaped at the base, with rounded teeth, somewhat hairy and wrinkled on the upper surface, and prominently veined and very hoary on the lower surface. The flowers are whitish, two-lipped, the upper lip two-lobed, the lower three-lobed, and are borne in dense, woolly clusters in the axils of the leaves. (Fig. 22.) The plant flowers from June to September, and the characteristic hooked calyx teeth of the mature flower clusters cling to the wool of sheep like a bur, resulting in the scattering of the seeds.
Fig. 22.—Hoarhound, flowering top.
Parts used.—The leaves and tops are used in medicine. These should be gathered just before the herb is in flower, rejecting the coarse stalks, and should be dried in the shade in the usual manner. The balsamic odor diminishes in drying. The herb has a bitter, persistent taste.
Hoarhound is well known as a remedy for colds, and is also used in dyspepsia and for expelling worms.
Imports and prices.—A considerable quantity of marrubium or hoarhound is imported, about 125,000 pounds coming into this country annually. Three to 8 cents is the price paid per pound.