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22. Randolph, L. Personal communication. 1948. 



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24. Rosen, G. Problems and methods in the production of tetraploids withm the 

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26. Sears, E. Personal communication. 1948. 



27. Smith, H. Personal communication. 1951. 



28. Smith, L. The aceto-carmine smear technique. Stain Tech. 22:17-31. 1947. 



29. Stebbins, G. Personal communication. 1951. 



30. Stewart, R. Personal communication. 1949. 



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