Gum Sonora. Sonora Gum. Covillea tridentata.

Gum Sonora. Sonora Gum.—According to Krewson, the exudation from Covillea tridentata (DC.) Vaill. (Larrea mexicana Moric.) contains 17.27 per cent. of resin, and 11.71 per cent. of mucilage and allied substances. (For details, see P. J., xvi, 128; also A. J. P., May, 1898.) Covillea tridentata is also known in Southwestern United States and Mexico as "Creosote bush," because of the odor of the oleoresin which covers the herbage.

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.