90 ON THE ORIGIN OF SPECIES 



the anthers burst before the stigma is ready for fertil- 

 isation, or the stigma is ready before the pollen of 

 that flower is ready, so that these plants have in fact 

 separated sexes, and must habitually be crossed. How 

 strange are these facts ! How strange that the pollen 

 and stigmatic surface of the same flower, though placed 

 so close together, as if for the very purpose of self- 

 fertilisation, should in so many cases be mutually 

 useless to each other ! How simply are these facts 

 explained on the view of an occasional cross with a 

 distinct individual being advantageous or indispen- 

 sable ! 



If several varieties of the cabbage, radish, onion, and 

 of some other plants, be allowed to seed near each 

 other, a large majority, as I have found, of the seedlings 

 thus raised will turn out mongrels : for instance, I 

 raised 233 seedling cabbages from some plants of 

 different varieties growing near each other, and of 

 these only 78 were true to their kind, and some even 

 of these were not perfectly true. Yet the pistil of each 

 cabbage-flower is surrounded not only by its own six 

 stamens, but by those of the many other flowers on the 

 same plant. How, then, comes it that such a vast 

 number of the seedlings are mongrelized ? I suspect 

 that it must arise from the pollen of a distinct variety 

 having a prepotent effect over a flower's own pollen ; 

 and that this is part of the general law of good being 

 derived from the intercrossing of distinct individuals 

 of the same species. When distinct species are crossed 

 the cas« is directly the reverse, for a plant's own pollen 

 is always prepotent over foreign pollen ; but to this 

 subject we shall return in a future chapter. 



In the case of a gigantic tree covered with innumer- 

 able flowers, it may be objected that pollen could 

 seldom be carried from tree to tree, and at most only 

 from flower to flower on the same tree, and that 

 flowers on the same tree can be considered as distinct 

 individuals only in a limited sense. I believe this 

 objection to be valid, but that nature has largely pro- 

 vided against it by giving to trees a strong tendency 



