Chap. IV. OF INTERCROSSING. 99 



C. C. Sprengel has shown, and as I can confirm, either the 

 anthers burst before the stigma is ready for fertilisation, 

 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 stig- 

 matic 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 indispensable ! 



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 sur- 

 rounded 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 inter- 

 crossing of distinct individuals of the same species. 

 When distinct species are crossed the case 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 innume- 

 rable flowers, it may be objected that pollen could seldom 

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



f2 



