xxviii MUTATION, MENDELISM, ETC. 



for fertilization. As regards some he showed the pro- 

 portion in which the different forms exist in the wild 

 state in various localities. 



5. He proved in many species that when a plant was 

 artificially fertilized by pollen from the same form, that 

 form immensely preponderated in the offspring. 



6. Such a union as that last described, which he called 

 ' illegitimate ', never yielded the full number of offspring. 

 From these facts he reached the following conclusion 

 given in his own words : ' The results of crossing such 

 flowers in an illegitimate manner, I believe to be very 

 important, as bearing on the sterility of hybrids ; although 

 these results have been noticed by only a few persons.' l 



7. Incidentally he produced much evidence that the 

 primrose, cowslip, and Bardfield oxlip are true species, 

 and that the common oxlip is a hybrid between the cow- 

 slip and the primrose, the latter investigation involving 

 many crossing experiments. 



8. Finally, he concluded with an extraordinarily inter- 

 esting and illuminating discussion on the distribution of 

 heterostyled species throughout the families of plants, on 

 the advantages of the heterostyled condition as compared 

 with other methods of securing cross-fertilization, and on 

 the steps by which plants may have become hetero- 

 styled. 



This last part of Darwin's great memoir is a conspi- 

 cuous example of the reasoning so severely condemned 

 by W. Bateson in his work on Variation. 2 I have now 

 summed up, far too briefly, the main results to the exposi- 



1 Life and Letters of Charles Darwin, London, 1887, vol. i, p. 97. 

 Certain aspects of this question are discussed on pp. 90-4 of the present 

 volume. 



2 Materials for the Study of Variation, London, 1894, pp. 10-13. See 

 also parts of the Preface to that book. 



