NATURAL SELECTION 145 



own flower, as I could show from the works of Sprengel 

 and others, as well as from my own observations: for 

 instance, in Lobelia fulgens, there is a really beautiful and 

 elaborate contrivance by which all the infinitely numerous 

 pollen-granules are swept out of the conjoined anthers of 

 each flower, before the stigma of that individual flower is 

 ready 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 seedlings. 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 re- 

 ceiving 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 dimorphic and trimorphic plants previously 

 alluded to. 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 pur- 

 pose of self-fertilization, 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 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 have found, mongrels: for instance, I raised 233 seed- 



— Science — 7 



