238 Hybridism. Chap. ix. 



with hybrid pollen of the same kind, their fertility, notwithstanding 

 the frequent ill effects from manipulation, sometimes decidedly 

 increases, and goes on increasing. Now, in the process of artificial 

 fertilisation, pollen is as often taken by chance (as I know from my 

 own experience) from the anthers of another flower, as from the 

 anthers of the flower itself which is to be fertilised ; so that a cross 

 between two flowers, though probably often on the same plant, 

 would be thus effected. Moreover, whenever complicated experi- 

 ments are in progress, so careful an observer as Gartner would have 

 castrated his hybrids, and this would have ensured in each genera- 

 tion a cross with pollen from a distinct flower, either from the same 

 plant or from another plant of the same hybrid nature. And thus 

 the strange fact of an increase of fertility in the successive genera- 

 tions of artificially fertilised hybrids, in contrast with those 

 spontaneously self-fertilised, may, as I believe, be accounted for by 

 too close interbreeding having been avoided. 



Now let us turn to the results arrived at by a third most experi- 

 enced hybridiser, namely, the Hon. and Eev. W. Herbert. He is 

 as emphatic in his conclusion that some hybrids are perfectly fertile 

 — as fertile as the pure parent-species — as are Kolreuter and Gartner 

 that some degree of sterility between distinct species is a universal 

 .aw of nature. He experimented on some of the very same species 

 as did Gartner. The difference in their results may, I think, be in 

 part accounted for by Herbert's great horticultural skill, and by his 

 having hot-houses at his command. Of his many important state- 

 ments I will here give only a single one as an example, namely, 

 that " every ovule in a pod of Crinum capense fertilized by C. 

 revolutum produced a plant, which I never saw to occur in a case 

 of its natural fecundation." So that here we have perfect or even 

 more than commonly perfect fertility, in a first cross between two 

 distinct species. 



This case of the Crinum leads me to refer to a singular fact, 

 namely, that individual plants of certain species of Lobelia, Ver- 

 bascum and Passiflora, can easily be fertilised by pollen from a 

 distinct species, but not by pollen from the same plant, though this 

 pollen can be proved to be perfectly sound by fertilising other plants 

 or species. In the genus Hippeastrum, in Corydalis as shown by 

 Professor Hildebrand, in various orchids as shown by Mr. Scott and 

 Fritz Miiller, all the individuals are in this peculiar condition. So 

 that with some species, certain abnormal individuals, and in other 

 species all the individuals, can actually be hybridised much more 

 readily than they can be fertilised by pollen from the same individual 

 plant ! To give one instance, a bulb of Hippeastrum aulicum pro- 



