146 TUE ORIGIN OF SPECIES 



ling 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 general 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 

 can be considered as distinct individuals only in a limited 

 sense. I believe this objection to be valid, but that 

 nature has largely provided against it by giving to trees 

 a strong tendency to bear flowers with separated sexes. 

 When the sexes are separated, although the male and 

 female flowers may be produced on the same tree, pollen 

 must be regularly carried from flower to flower; and this 

 will give a better chance of pollen being occasionally 

 carried from tree to tree. That trees belonging to all 

 Orders have their sexes more often separated than other 



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