OF INDIVIDUALS. 91 



carry pollen from one to the other, to the great good of the 

 plant. Insects act like a camel-hair pencil, and it is suffi- 

 cient, to insure fertilization, just to touch with the same 

 brush the anthers of one flower and then the stigma of 

 another; but it must not be supposed that bees would thus 

 produce a multitude of hybrids between distinct species; 

 for if a plant's own pollen and that from another specie* 

 are placed on the same stigma, the former is so prepotent 

 that it invariably and completely destroys, as has" been 

 shown by Gartner, the influence of the foreign pollen. 



When the stamens of a flower suddenly spring toward 

 the pistil, or slowly move one after the other toward 

 it, the contrivance seems adapted solely to ensure self- 

 fertilization; and no doubt it is useful for this end: but 

 the agency of insects is often required to cause the stamens 

 to spring forward, as Kolreuter has shown to be the case 

 with the barberry; and in this very genus, which seems to 

 have a special contrivance for self-fertilization, it is well 

 known that, if closely-allied forms or varieties are planted 

 near each other, it is hardly possible to raise pure seedlings, 

 60 largely do they naturally cross. In numerous other 

 cases, far from self-fertilization being favored, there are 

 special contrivances which effectually prevent the stigma 

 receiving pollen from its 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 

 fhat 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 receiving pollen from the same flower, yet, as 

 Sprengel, and more recently Hildebrand and others liave 

 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 

 ^o-named dichoganiotis plants have in fact separated sexes^ 



