Issued in preliminary mimeographed form, 1936, with title: Handbook of native woody plants of the United States (SCS-TP-11). The maps have distinctive authors and titles and are sometimes referred to as separate works: Plant growth regions of the United States, by F.L. Mulford; Climatic provinces and plant growth regions of the United States, by C.W. Thornthwaite and F.L. Mulford; Important soil regions and plant growth regions of the United States, by Bureau of chemistry and soils and F.L. Mulford.