334 BOTANICAL GAZETTE [October 



Here, as in the larger family Rosaceae, we have 

 of admitted hybrids in certain genera (Epilobium 



nized species. In other cases the recognized 



same 



characteristic of hybrids. This state of affairs is found to a very 

 large and striking degree in the genus Oenothera. Since the species 

 of Oenothera to a very considerable extent, particularly those which 

 have been used in investigations of a mutational or genetical nature 

 (0. Lamarcktana, 0. biennis, etc.), are under the strongest possible 

 suspicion of hybrid origin, it follows that any conclusions drawn 

 from their genetical behavior, in connection with the vexed problem 

 of the origin of species, must be subject to a large degree of reserve. 

 So far as the conduct of O. Lamarckiana and other species of the 



oblem 



rith the multiplication 

 matter indeed from tl 



mutation 



strongly emphasized for animals by Gerould. 3 The reader is 



lm 



the zoological side, for an expression of views very similar to the 

 conclusions reached in the present article in the case of plants. 

 In plants we have the great advantage of being able to a very large 

 extent to supplement genetical and taxonomic data by the examina- 

 tion of internal organization. 



The writer 4 has previously made a general statement on the 

 questions here involved. Gates 5 has recently published an article 

 in which he attempts to show that mutation and hybridization 

 are independent phenomena. His conclusions seem to be fatally 

 invalidated by the fact that his experiments were carried on upon 

 Oenothera species and "mutants." The situation is apparently 

 the same as would present itself if a chemist worked with impure 

 chemicals or a physicist with mixed radiations. 



^ Species-making by hybridization and mutation. Amer. Nat. 48: no. 570. 

 «The mutation myth. Science N.S. 39:488-491. 1914, 



5 Breeding experiments which show that hybridization and mutation are inde- 

 pendent phenomena. Zeitschr. Induktive Abst. und Vererb. 2: Heft 4- 



