Chap. IV.] OP INDIVIDUALS. 121 



self-fertilisation; and no doubt it is useful for this end: 

 but the agency of insects is often required to cause the 

 btamens 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-fertilisation, 

 it is well-known that, if closely-allied forms or varieties 

 are planted near each other, it is hardly possible to raise 

 pure seedlings, so largely do they naturally cross. In 

 numerous other cases, far from self-fertilisation being 

 favoured, there are special contrivances which effectu- 

 ally 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 in- 

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

 elaborate contrivance by which all the infinitely numer- 

 ous pollen-granules are swept out of the conjoined an- 

 thers 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. An- 

 other 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 fertilisation, 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! 



