122 ON THE INTERCROSSING [Chap. IV. 



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 be in so many 

 cases 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 indis- 

 pensable! 



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

 of some other plants, be allowed to seed near each other, 

 a large majority of the seedlings thus raised turn out, as I 

 have found, 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; and the pollen of each 

 flower readily gets on its own stigma without insect 

 agency; for I have found that plants carefully protected 

 from insects produce the full number of pods. How, 

 then, comes it that such a vast number of the seedlings 

 are mongrelized? It must arise from the pollen of a 

 distinct variety having a prepotent effect over the 

 flower's own pollen; and that this is part of the gen- 

 eral law of good being derived from the intercrossing of 

 distinct individuals of the same species. When distinct 

 species are crossed the case is reversed, for a plant's own 

 pollen is almost always prepotent over foreign pollen:, 

 but to this subject we shall return in a future chapter. 



In the case of a large tree covered with innumerable 

 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 flowers on the same tree 



