154 TORRE Y A 



Timofeeff-Ressovsky, N. W. 1940. Mutations and geographical variation, pp. 73-136 in 

 The New Systematics by Huxley. 



TuRESSON, G. 1925. The plant species in relation to habitat and climate. Hereditas 6: 147- 

 236. 



. 1932. Die Genezentrumtheorie und das Entwicklungszentrum der Pflanzenart. 



Kungl. Fysiogr. Sallsk. i Lund Fordhl. 2: (6). 



Vavilov, N. I. 1927. Geographical regularities in the distribution of the genes of culti- 

 vated plants. Bull. Applied Bot. 17 (3) : 420-428. [Russian with English summary.] 



. 1928. Geographische Genzentren unserer Kulturpflanzen. Verhandl. V. Intern. 



Kongr. Vererbungswissenschaft. Berlin. 



. 1940. The new systematics of cultivated plants, pp. 549-566 in The New Systema- 



tics by Huxley. 

 Willis, J. C. 1922. Age and Area. Cambridge. 

 . 1940. The Course of Evolution. Cambridge. 



