iguj] VESTAL— PI1YT0GE0GRAPIIY OF COLORADO 193 



13. Robbins, W. W., Climatology and vegetation in Colorado. Bot. Gaz. 

 49:256-280. 1910. 



14. , Native vegetation and climate of Colorado in their relation to 



agriculture. Bull. 224, Agric. Exp. Sta. of the Colo. Agric. Coll. 56 pp. 

 1917. 



15. Shantz, H. L., A study of the mesa region east of Pike's Peak: the Boute- 

 loua formation. Bot. Gaz. 42:16-47, 179-207. 1906. 



16. , Natural vegetation as an indicator of the capabilities of land for 



crop production in the Great Plains area. U.S. Dept. Agric, Bur. PI. 

 Industry, Bull. 201. pp. 100. 191 1. 



17. Vestal, A. G., Prairie vegetation of a mountain-front area in Colorado. 

 Bot. Gaz. 58:377-400. 1914. 



18. , Foothills vegetation in the Colorado Front Range. Bot. Gaz. 



64:353-385- 1917- 



19. Ward, R. De C, Rainfall types of the United States. Geog. Review 



4:131-144. 1917. 



20. Weaver, J. E., Evaporation and plant succession in southeastern Wash- 

 ington and adjacent Idaho. Plant World 17:273-294. 1914. 



