Further Observations on the Selective Elimination of Ovaries in Staphylea. 17 7 



ovules. Yet the selective elimination for radial asymmetry and locular 

 composition is as thoroughly established as that for number of ovules. 

 The burden of proof should, therefore, really fall upon the critic. 



A thorough-going investigation of the hypothesis under discussion 

 demands : 



(a) The demonstration that there is a progressive change in the 

 characters of the ovaries as one passes from the base to the 

 tip of the inflorescence. 



(b) The demonstration that in the elimination after flowering a 

 certain region or regions of the inflorescence, e. g. the tip, 

 contributes an excessive proportion of ovaries. 



(c) The demonstration on the basis of statistics taking into account 

 a) the percentage of the original number of ovaries which are 



eliminated, 

 ß) the number of ovaries occupying each position on the in- 

 florescence and the proportionate elimination from each 

 position, 

 y) the extent of differentiation in ovaries due to their position 



on the inflorescence, 

 8) the difference between eliminated and developing ovaries, 

 that the differentiation due to position on the inflorescence is ample 

 under these four conditions to accoimt for the observed differences 

 between matured and eliminated ovaries. 



The collection of the necessary data for a final proof would be 

 very difficult, if not impossible, in a large shrub like Staphylea and 

 I have not been able to approximate it. In the spring of 1906, 

 preliminary countings of developing ovaries were made and refined 

 work on the inflorescence could not be undertaken; in the spring of 

 1907, a severe frost killed a high proportion of the flowers ; in the 

 spring and summer of 1908, nothing more than the collection of over 

 7000 ovaries for the selective elimination tests could be attempted; 

 the year elapsing between the spring of 1908 and that of 1909 had 

 not been sufficient to allow the working up of the material gathered 

 in 1908, and it seemed inadvisable to collect more data until it could 

 be done with the benefit of the results from the 1908 series; in 1910, 

 when an extensive study of some phases of the selective elimination 

 problem had been undertaken, a severe cold wave again put a summary 

 end to the work. 



At present, I do not anticipate an opportunity to make a further 

 study of the young inflorescence of Staphylea. Under these circum- 



Induktive Abstammungs- und Vererbungslehre. V. 12 



