78 THE ORIGIN OF SPECIES 



to receive them; and as this flower is never visited, at least in my 

 garden, by insects, it never sets a seed, though by placing pollen 

 from one flower on the stigma of another, I raise plenty of seed- 

 lings. Another species of Lobelia, which is visited by bees, seeds 

 freely in my garden. In very many other cases, though there is no 

 special mechanical contrivance to prevent the stigma receiving 

 pollen from the same flower, yet, as Sprengel and more recently 

 Hildebrand and others have shown, and as I can confirm, either 

 the anthers burst before the stigma is ready for fertilization, or the 

 stigma is ready before the pollen of that flower is ready, so that 

 these so-named dichogamous plants have in fact separated sexes, 

 and must habitually be crossed. So it is with the reciprocally di- 

 morphic and trimorphic plants previously alluded to. How strange 

 are these facts! How strange that the pollen and stigmatic sur- 

 face of the same flower, though placed so close together, as if for 

 the very purpose of self-fertilization, should be in so many cases 

 mutually useless to each other! How simply are these facts ex- 

 plained 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 of 

 the seedlings thus raised turn out, as I found, mongrels: for in- 

 stance, I raised 233 seedling cabbages from some plants of differ- 

 ent 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 stigma 

 without insect agency; for I have found that plants carefully pro- 

 tected 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 pre- 

 potent 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 



