Further Observations on the Selective 

 Elimination of Ovaries in Staphylea. 



By J. Arthur Harris. 



I. Introductory. 



In Staphylea trifolia, an American shrub belonging to the Sapin- 

 daceae, only a small proportion of the flowers produce mature fruits. 

 In another place^), I have shown that the ovaries which fail to develop 

 to maturity differ from those which become fruits. In fact, there is 

 a selective elimination among the organs of the individual analogous 

 to the natural selection which has been the fundamental conception 

 of the Darwinian Theory. By this selective elimiiiation, the following 

 changes in the character of the series of ovaries borne by an individual 

 are produced: 



(a) An increase in the number of ovules. 



(b) A decrease in the variability of number of ovules. 



(c) A decrease in the radial asymmetry of the ovary as measured 

 by the standard deviation of the number of ovules per locule 

 around the mean of their own ovary. 



(d) A decrease in the proportion of ovaries with one or more 

 locules with an odd number of ovules. 



(e) Possibly an increase in the number of locules per ovary. 



At the time of sending my memoir to press I was quite aware 

 that it was liable to be criticised in certain details by fellow workers 

 who might feel that well-known biological principles had been ignorantly 

 disregarded or deliberately ignored. The reasons for omitting all refe- 

 rence to these questions are three-fold. 



First. I wanted that paper to deal strictly with the facts, with 

 the measurable intensity, of selective elimination. I did not want 



1) Harris, J. Arthur, On the Selective EUmination occurring during the 

 Development of the Fruits of Staphylea trifolia, Biometrika, vol. VII, pp. 452 — 504, 

 1910: also. The Selective Elimination of Organs. Science, N. S. vol. XXXII, 51Q — 

 528, 1910. 



