188 University of California PuMications in Botany [Vol. 5 



Tower, W. L. 



1902. Variation in the ray-flowers of Chrysanthevium leiicanthemum L. 

 at Yellow Springs, Green County, Ohio, with remarks on the 

 determination of modes. Biometrika, vol. 1, pp. 309-315. 



1906. An investigation of evolution in Chrysomelid beetles of the 

 genus Lei^tinotarsa. Carnegie Inst. Publ., no. 48, pp. 93-105. 



