ALLEN: EVOLUTION OF SEXUAL CHARACTERS 15 



many for femaleiiess. The elements which constitute this mechanism at any 

 particular period in the history of a species influence in various ways and in 

 varying degrees the development and functioning of stamens and pistils ; they 

 influence also the numbers and arrangement of these organs, whether in the 

 same or in separate flowers, as well as the time of appearance of the respective 

 flowers and their positions on the plant. 



Department of Botany 

 University of Wisconsin 

 Madison, Wisconsin 



Literature Cited 



Most of the studies referred to in the present paper are cited in the first article listed 

 below. For this reason only a few references to specific papers have been included. 



L Allen, C. E. The genotypic basis of sex-expression in angiosperms. Bot. Rev. 6: 227- 

 300. 1940. 



2. Correns, C. Die Bestimmung und Vererbung des Geschlechtes nach neuen Versuchen 

 mit hoheren Pflanzen. 1907. 



3. . Bestimmung, Vererbung und Verteilung des Geschlechtes bei den hoheren 



Pflanzen. Handbuch der Vererbungswissenschaften (Baur and Hartmann) II, C. 

 1928. 



4. Crane, M. B., and W. J. C. Lawrence. The genetics of garden plants. 2d ed. 1938. 



5. Emerson, R. A. A genetic view of sex expression in the flowering plants. Science 

 N. S. 59: 176-182. 1924. 



6. . The present status of maize genetics. Proc. 6th Int. Congr. Genetics 1: 141-152. 



1932. 



7. , G. W. Beadle, and A. C. Eraser. A summary of linkage studies in maize. 



Cornell Univ. Agr. Exp. Sta. Mem. 180. 1935. 



8. Jones, D. F. Dioecious maize. Science N. S. 73: 432. 1931. 



9. •. Unisexual maize plants and their bearing on sex differentiation in other plants 



and in animals. Genetics 19: 552-567. 1934. 



10. Lewis, D. Male sterility in natural populations of hermaphrodite plants. New Phytol. 

 40: 56-63. 1941. 



11. . The evolution of sex in flowering plants. Biol. Rev. 17: 46-67. 1942. 



12. Nagai, J. Studies on the mutations in Orysa sativa L. I-IV. Jap. Jour. Bot. 3: 25-96. 

 1926. 



13. Ono, T. Chromosomen und Sexualitat von Rumcx Acetosa. Sci. Repts. Tohoku Imp. 

 Univ. 4th Ser. Biol. 10: 41-210. 1935. 



14. OsTENFELD, C. H. Castration and hybridisation experiments with some species of 

 Hicracia. Bot. Tidskr. 27: 225-248. 1906. 



15. Rhoades, M. M. The cytoplasmic inheritance of male sterility in Zca Mays. Jour. 

 Genet. 27: 71-93. 1933. 



16. SuNESON, C. A. A male sterile character in barley. Jour. Hered. 31.: 213, 214. 1940. 



17. Warmke, H. E., and A. F. Blakeslee. Sex mechanism in polyploids of Melandrium. 

 Science N. S. 89: 391, 392. 1939. 



18. Wettstein, F. Uber Fragen der Geschlechtsbestimmung bei Pflanzen. Naturwiss. 

 12: 761-768. 1924. 



19. Wettstein, R. Handbuch der systematischen Botanik. 4th ed. 1935. 



20. Yampolsky, C, and Helene Yampolsky. Distribution of sex forms in the phanero- 

 gamic flora. Biblioth. Genet. 3: 1-62. 1922 



