June, 11)1 <j Xenia Folloiving Fertilization 283 



eggs, or in the uterus of the mother which would in turn affect 

 the eggs, so that even after these eggs were fertilized from 

 another father there would still remain some influence of the 

 previous one. 



In ectogony a change takes place outside the region of 

 fertilization as a result of a new influence produced by the devel- 

 oping zygote. In xenia, on the other hand, a change that is 

 more apparent than real is produced, since the new heredity 

 introduced by the male nucleus consists of determiners that 

 must express themselves in the same way that they would 

 in the race to which they are native. There is nothing different 

 from the normal, nothing unusual actually taking place in 

 xenia, simply old determiners in a new place offer a surprise. 



Xenia can frequently be successfully employed to separate 

 cross pollinated from close fertilized kernels in maize, as the 

 writer (16) recently indicated, and its practical advantages 

 from the geneticist's standpoint are far reaching. The whole 

 subject, however is practically unexamined by investigators 

 to date and offers an inviting field in which much good work 

 can be done. 



Apart from the usefulness of xenia and apart from general 

 interest in it as a fit subject for future investigation, the signifi- 

 cance of the word has been brought into the widest botanical 

 consideration by the introduction of the term xeniophyte. 

 This reason is, per se, sufficient for retaining the meaning of 

 xenia in its strict definiteness. If a distinction among influences 

 following fertilization is to be made at all, the place to begin 

 classifying the different effects is where the morphological 

 evidence shows that a natural separation exists. 



The opportunity is welcomed to make public acknowledg- 

 ment of the gratitude felt toward Professor John H. Schaffner, 

 of the Ohio State University, for helpful criticism and guidance 

 during and before the time that the above paper was in 

 preparation. 



Summary. 



Xenia is a phenomenon limited to the endosperm of 

 angiosperms. 



The xeniophyte, like the sporophyte, is a product of fusion. 

 In the latter the egg nucleus and one male nucleus fuse; in the 

 former there is fusion between the second male nucleus and the 



