DEGREES OF STERILITY, 281 



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

 experienced hybridizer, namely, the Hon. and Rev. 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 law 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 horticul- 

 tural skill, and by his having hot-houses at his command. 

 Of his many important statements I will here give only a 

 single one as an example, namely, that "every ovule in a 

 pod of Orinum capense fertilized by C. revolutum pro- 

 duced 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 Orinum leads me to refer to a singular 

 fact, namely, that individual plants of certain species 

 of Lobelia, Verbascum and Passiflora, can easily be fer- 

 tilized by the pollen from a distinct species, but not by 

 pollen from the same plant, though this pollen can be 

 proved to be perfectly sound by fertilizing other plants or 

 species. In the genus Hippeastrum, in Oorydalis 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 hybridized much more readily 

 than they can be fertilized by pollen from the same indi- 

 vidual plant! To give one instance, a bulb of Hippeas- 

 trum aulicum produced four flowers; three were fertilized 

 by Herbert with their own pollen, and the fourth was sub- 

 sequently fertilized by the pollen of a compound hybrid 

 descended from three distinct species: the result was that 

 "the ovaries of the three first flowers soon ceased to grow, 

 and after a few days perished entirely, whereas the pod 

 impregnated by thepollen of the hybrid made vigorous 

 growth and rapid progress to maturity, and bore good seed, 

 which vegetated freely.'' Mr. Herbert tried simihir experi- 

 ments during many years, and always with the same result. 

 These cases serve to show on what slight and mysterious 



