Pool : THE VEGETATION OF THE SANDHILLS OF NEBRASKA 309 



13. . Were the sandhills of Nebraska formerly cov- 

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14. . The origin of the flora of Nebraska. Pub. Neb 



Acad. Sci. 5:33. 1896. (Abstract.) 



15. . The forests and forest trees of Nebraska. Ann. 



Rep. Neb. State Board Agri. 1899. 



16. . Vegetation of the sandhills. Ann. Rep. Neb. 



State Board Agri. 1900. 



17. . Plant migration studies. Uni. Neb. Studies 



5: No. 1. 1905. 



18. Bessey, C. E., and Webber, H. J. See Webber, H. J., and 

 Bessey, C. E. 



19. Briggs, L. J., and Belz., J. O. Dry farming in relation to 

 rainfall and evaporation. U. S. Dept. Agri., Bur. Plant Ind., 

 Bui. 188. 1910. 



20. Clements, F. E. Peculiar zonal formations of the great plains. 

 Am. Nat. 31 : 968. 1897. 



21. . Zonal constitution and disposition of the plant 



formations. Rep. 67th meeting British Assn. Adv. Sci. 1897. 



22. , and Pound, R, See Pound, R., and Clements, 



F. E. 



23. . The development and structure of vegetation, 



Bot. Surv. Neb. VII. Studies in the vegetation of the state 

 III. 1904. 



24. . Research methods in ecology. 1905. 



25. . Plant physiology and ecology. 1907, 



26. Cockayne, L. Report on the dune-areas of New Zealand, 

 their geology, botany and reclamation. Department of Lands, 

 N. Z. 1911. 



27. Coons, G. H. A biological survey of the sand dune region 

 on the south shore of Saginaw Bay, Michigan. Ecological 

 relations of the flora. Geol. and Biol. Surv. Mich., Pub, 4. 

 Biol, series 2 : 35-64. 1911. 



28. Condra, G. E. The geography of Nebraska. 1908. 



29. Cornish, V. On the formation of sand dunes. Geog. Journ. 

 9:278. 1892. 



30. Cowles, H. C. The ecological relations of the vegetation of 

 the sand dunes of Lake Michigan. Bot. Gaz. 27:95-117, 

 167-202, 281-308, 361-391. 1899. 



31. . The physiographic ecology of Chicago and 



