74 J^xperiments with Primula sinensis 



Introduction. 



The experiments, of which the present paper is the outcome, were 

 begun in 1903 by Mr Bateson and the present writer jointly, and in 

 1905 we published an account of our observations up to that time upon 

 the inheritance of heterostylism^ Although I am alone responsible 

 for the views put forward in the present paper, and for any errors 

 which it may contain, the work with which it deals has been done in 

 association with Mr Bateson, to whom much of such progress as has 

 been made is due. Mr Bateson has given me the most generous help, 

 not only in the elucidation of the results, but also in the practical 

 business of carrying on the experiments. I am further indebted to 

 him for giving house room to a large number of plants each year. 



The plates illustrating the various coloured forms which have been 

 met with in the course of the experiments are reproduced from the 

 beautiful and accurate water-colour drawings of Miss M. Wheldale, of 

 Newnham College, Cambridge. 



I wish to take this opportunity of acknowledging again my in- 

 debtedness to Messrs Sutton and Sons, who have most kindly given 

 assistance in many ways during the course of this enquiry. 



My thanks are due also to the Botanic Garden Syndicate of Cam- 

 bridge University, and to Mr R. I. Lynch, Curator of the Botanic 

 Gardens, for the provision of housing, materials and labour. 



The principal objects of our investigations in Primula sinensis have 

 been the inheritance of heterostylism and of colour. At the same time 

 records have been kept of certain other characters, the inheritance of 

 which has been found to be, for the most part, of a simple type and 

 does not require any special comment here^ 



Heterostylism^. The dearth of short-styled plants occurring in the 

 families raised from the self-fertilized heterozygote, which was noticed 

 in our earlier experiments, is still maintained even in the larger 

 numbers now obtained. On the other hand the same plants, crossed 

 by the long-styled, give an excess of short-styled offspring. Our results 

 do not as yet give a decisive answer as to whether these divergences, 



1 Bateson and Gregory, Roy. Soc. Proc. B, Vol. 76, 1905, pp. 581—586. 



'■^ Some of these results have already been mentioned; see Bateson : "The progress of 

 Genetics since the rediscovery of Mendel's papers," Prog. Rei. Bot., Vol. i. 1907, pp. 373, 

 383 ; Mendel's Principles of Heredity, Camb. Univ. Press, 1909. Gregory: "The inherit- 

 ance of certain characters in Primula sinensis," Brit. Assoc. Rep., Leicester, 1907, 

 pp. 691—693. 



3 Bateson and Gregory, I.e. 



