Benson, Lyman; and Darrow, Robert: A Manual of Southwestern Trees and Shrubs; University of Arizona, 1944.

Benson, Lyman: The Cacti of Arizona; University of Arizona, Second Edition, 1950.

Black, Homer: Common and Larger Plants Near the Cavern Entrance; Carlsbad Caverns National Park; mss. 1944.

Cooper, Norman C.: Check List of Plants of Organ Pipe Cactus National Monument; mss. 1942.

Jaeger, Edmund C.: Desert Wildflowers; Stanford University Press, Revised Edition, 1944.

Joint Committee on Horticultural Nomenclature: Standardized Plant Names; Second Edition, 1942.

Kearney, Thomas H.; and Peebles, Robert H.: Flowering Plants and Ferns of Arizona; Government Printing Office, 1942.

McDougall, W. B.: Vegetation of White Sands National Monument; mss. 1939.

McDougall, W. B.: Check List of the Plants of Death Valley National Monument; mimeo. 1945.

McDougall, W. B.; and Sperry, Omer E.: Plants of Big Bend National Park; Government Printing Office, 1951.

Nichol, A. A.: The Natural Vegetation of Arizona; University of Arizona Technical Bulletin No. 68, 1937.

Shantz, H. L.; and Piemeisel, R. L.: Indicator Significance of the Natural Vegetation of the Southwestern Desert Region; Government Printing Office, 1925.

Sperry, Omer E.; and Warnock, Barton H.: Plants of Brewster County, Texas; Sul Ross State Teachers College Bulletin, Vol. 21, No. 1, Alpine, Texas, 1941.

Taylor, Walter P.; McDougall, Walter B.; and Davis, William B.: Preliminary Report of an Ecological Survey of Big Bend National Park; March-June, 1944; mimeo.