INDIAN HOREHOUND, in botany: A genus of the monogynia order, belonging to the dianthria clas of plants; and in the natural method ranking under the 42d order, Periclitatae. The corolla is unequal, with the upper lip linear, involving the filaments; there are four seeds. The most remarkable species is the zeylanica, a native of the East Indies. It rises with an herbaceous, four-cornered, hoary stalk, and bears leaves that are entire, nearly heart-shaped, woolly, deep notched on the edges, and having footstalks. The flowers, which are purplish and fragrant, surround the stalk in whorls, each whorl containing about 14 flowers; and are succeeded by four small kidney- Monardee kidney-shaped shining seeds, lodged in the bottom of the permanent flower-cup. The Indians superstitiously believe that a fumigation of this plant is effectual for driving away the devil; and from this imaginary property its name in the Ceylonese language is derived. Grinnius relates, in his Laboratorium Ceylonicum, that for taste and smell this species of horehound stands remarkably distinguished. A water and subtile oil are obtained from it, both of which are greatly commend ed in obstructions of the matrix. A syrup is likewise prepared from this plant, which is useful in the above-mentioned disorders as well as in diseases of the stomach.