AN ANALYTICAL KEY TO SOME OF THE SEGREGATES OF 

 OENOTHERA. 



BY REGINALD R. GATES. 



This little key is published with the idea of aiding botan- 

 ists in America and Europe, who have no special knowledge 

 of or acquaintance with the forms concerned, in identifying 

 some of the recent segregates and mutants of Oenothera as 

 they are now recognized on the basis of the pedigree cultures 

 of recent years. Since some of these forms, such as 0. 

 grandijlora, are known still to occur in the wild condition, and 

 since some of them are liable to be discovered at any time 

 in a new locality, it is important that botanists in general 

 should have available a brief analytical key with mention of 

 the chief differentiating characters and references to some of 

 the best illustrations and descriptions of the various forms. 



As an instance of the necessity for this may be mentioned 

 a recent experience of the writer, whose attention was called 

 to a large flowered evening primrose growing in the back 

 yard of a citizen of Saint Louis, Mr. Ernest F. Achle, 5143 

 Page Avenue. The large flowers attracted attention and a 

 specimen was brought for identification. An examination of 

 the plant showed that it is very probably a form or deriva- 

 tive of 0. grandijlora. This plant is at present only known 

 from two localities in Alabama, and the source from^ which 

 this particular specimen reached its present location is quite 

 unknown. But it is by no means unlikely that search by 

 botanists and collectors will reveal its presence in various 

 parts of the country. Probably the most likely location in 

 which to look for 0. grandijlora is in the States of the 

 Middle South. I may say that cultures of some English 

 Oenotheras growing wild near Liverpool, an account of 

 which is as yet unpublished,* show that various races of 

 0. grandijlora, as well as 0. Lamarckiana and its deriva- 

 tives, occur in that locality. 



* See Proceedings British Assoc. Adv. Sci. , Sec. K. Winnipeg meeting, 



1909. 



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