Breeding experiments which sho-w that 

 hybridisation and mutation are independent 



phenomena. 



By R. R. Gates. Ph. D., F. L. S. 



University of London. 



(Eingegangen: 30. September 191 3.) 



Contents. 



page 



I. Introduction 209 



II. Description 212 



O. grandißoni X O. mut. rubticalyx, and its reciprocal 212 



A. Methods 212 



B. The ancestors of the crosses 213 



C. Collateral experiments 224 



C. I. The parent types, O. grandiflora and O. riibricalyx 227 



D. O. grandiflora X O. mut. riibricalyx, and its reciprocal. Fi 228 



E. I. 0. grandiflora X O. mut. riibricalyx, and its reciprocal. F., 234 



E. 2. Inheritance of the riibricalyx character, 7? 238 



E. 3. The variability of the riibricalyx character, R 244 



F. Inheritance of the recessive unit-character, / 246 



G. Other bud characters 249 



H. Foliage characters 253 



I. Inheritance of time of flowering 256 



J. Double reciprocal crosses 261 



K. The occurrence of mutations 264 



III. Discussion 268 



IV. Summary and Conclusions 272 



V. Bibliography 277 



VI. Explanation of plates 278 



I. Introduction, 



In the following paper I shall describe the results of crosses between 

 certain Oenotheras which differ from each other in a great number of 

 characters and which may therefore be regarded as equivalent to 

 interspecific crosses. Incidentally I shall show that the mutations, 



Induktive Abstammuitgs- und Vererbungslehre. XI. 14 



