484 



Mr. R. P. Gregory. 



EEFEEENCES. 



Grey, E. C, ' Biochem. Journ.,' vol. 7, p. 359 (1913). 



Grey, E. C, this vol., p. 461 (1914). 



Harden, A., ' Chem. Soc. Journ.,' p. 610 (1901). 



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Harden and Penfold, ' Proc. Eoy. Soc.,' B, vol. 85, p. 415 (1912). 



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Penfold, W. J., 'Proc. Roy. Soc. Med.,' p. 97 (1911). 



Ryffel, 'J. Physiol.,' vol. 39, 'Proc.,' p. v (1909). 



On the Genetics of Tetraploid Plants in Primula sinensis. 



By E. P. Gregory, M.A., 'Fellow of St. John's College, Cambridge, 

 University Lecturer in Botany. 



(Communicated by W. Bateson, F.B.S. Beceived March 3, — Read 

 April 30, 1914.) 



The purpose of this paper is to describe certain peculiar results obtained in 

 the genetics of two " giant " races of Primula sinensis. Cytological investi- 

 gation has shown these giants, unlike the giant races already described,* 

 to be in the tetraploid condition, that is to say, that whereas in ordinary 

 Primulas the chromosomes are x (12) in the gametic and 2x (24) in the 

 somatic stage, in the tetraploid giants the chromosomes are 2a? (24) in the 

 gametic and, as nearly as can be counted, 4x (48) in the somatic cells. 



Nilsson-Ehlef and EastJ have shown that factors of similar property may 

 be reduplicated in the same zygote (or gamete), with various peculiar 

 numerical consequences not otherwise intelligible, notably the appearance 

 in certain F 2 -families of such ratios as 15D : IB, 63D : IB, and so on, when 

 in the ordinary case 3 : 1 would be expected. The occurrences to be 

 described in part recall this phenomenon ; but, as will be seen, they are 



* Gregory, 'Camb. Phil. Soc. Proc.,' vol. 15, p. 239 (1909) ; Keeble, 'Journ. Genetics,' 

 vol. 2, p. 163 (1912). 



t " Kreuzungsuntersuchungen an Hafer und Weizen, I and II," 'Lunds Univ. 

 Arsskrift,' 1909 and 1911 ; ' Berichte d. Deutschen Botanischen Gesellschaft,' vol. 29, 

 p. 65 (1911). » 



% 'American Naturalist,' vol. 44, p. 65 (1910). 



