MEASUREMENT OF NATURAL SELECTION 



535 



complex phases and devoted ourselves temporarily to the morphological 

 and physiological problems upon which they rest. 



While testing out this idea in studies of the relationship between 

 structural characteristics and fertility in various fruits, certain incon- 

 sistencies in results were found which could be most easily explained 

 by the assumption that there is a selective elimination in which ovaries 



Fig. 5. Compabison or matubed Fedits with fallen Ovaeies foe twenty- 

 eight individual Shbubs of Staphylea. Differences expressed in percentages of the 

 mean of the eliminated series. Solid dots and broken lines = mean number of ovules ; 

 circles and firm lines = radial asymmetry. 



of certain types are extensively weeded out. Direct investigation proved 

 the correctness of this assumption. The results will be set forth very 

 briefly. 26 



In the selective elimination which occurs during the development 

 of the ovary of the American bladder nut, Staphylea, into a fruit, the 



28 Those who care for a detailed account may find it in three papers: (a) 

 "Is there a Selective Elimination in the Fruiting of the Leguminosse ? ' ' Amer. 

 Nat., Vol. XLin., pp. 556-559, 1909; (6) "On the Selective Elimination during 

 the Development of the Fruits of Staphylea," Biometrika, Vol. VII., pp. 452- 

 504, 1910; (c) "On the Selective Elimination of Organs," Science, n. s., Vol. 

 XXXII., pp. 519-528, 1910. 



