This 1938 addition to the Renaissance Revival style Botany Building (formerly Natural Science) offers an excellent example of the importance of Public Works Administration funds during the Depression Era to the expansion of the University of Montana. The U-shaped annex of brick and glass originally contained a fully equipped botanical laboratory, experimental animal rooms, and a greenhouse. Equipped now solely for use by the Botany Department, the annex, with its red-brown exterior and hipped roof, was carefully designed to be architecturally compatible with the older building.