XENIA, OR THE IMMEDIATE EFFECT OF POLLEN, IN 



MAIZE. 



INTIIODUCTION, 



The supposed immediate or direct effect of ]iollen on the character 

 of seeds and fruits, which was termed xenia ))y Focke,' is a phenom- 

 enon which for ycavH has puzzled botanists and plant breeders. Until 

 recently no satisfactory theory had been advanced to explain how 

 the influence of hybridization could pass outside of the fecundated 

 embryo and cause changes in other portions of the seed or fruit. 

 However, in a recent preliminary article " On the hybrid fecundation 

 of the albumen," De Vries"^ calls attention to the discovery of double 

 fecundation as probably furnishing an explanation of the phenomenon 

 of xenia. Almost simultaneously with the appearance of De Vries's 

 paper, Correns^ published a summary of his studies on xenia in maize 

 in which the same conclusion is reached. 



In discussing the bearing of double fecfindation on the problems of 

 hybridization with Prof. De Vries in July, 1899, this prolmble explana- 

 tion of xenia occurred to the writer independently, and during that 

 summer quite a number of experiments were conducted with a view 

 to obtaining evidence on this question. These experiments, while not 

 complete, have already yielded suggestive results, and it is thought 

 best to publish them now while the matter is under discussion rather 

 than to wait until the completion of the work. 



Double fecundation was first observed in Lilium ma/rtagon and Fri- 

 tillaria tenella by Nawaschin* and reported at the meeting of the 

 Botanical Section of the Russian Society of Naturalists, August 24, 1898. 



1 Focke, W. O. Die Pflanzen-Mischlinge, p. 511. 1881. 



''De Vries, Hugo. Sur la fecondation hybride de ralbumen. Comptes rendus d. 

 seances d. I'Acad. d. Sci.,T. 129, pp. 973-975. 4 Dec, 1899. 



* Correns, C. Untersuchungen iiber die Xenien bei Zea Mays. Berichte d. Deut. 

 Bot. Gesellsch., Bd. 17, pp. 410-417. December, 1899. 



*Nawaschin, S. Resultate einer Revision des Befruchtungsvorgangs bei Lilium 

 Martagon und Fritillaria tenella. Bui. d. I'Acad. Imp. d. Sciences de St. Peters- 

 bourg, T. 9, No. 4, 1898. Also Botanisches Ceutralblatt, Bd. 77, p. 62, 1899. 



7 



