GARTNER'S INFERENCES. 



Hybrids were obtained between the species MirabUis Jalapa and M. 

 longiflora. A plant of the latter was crossed with the former, but not 

 one fertile seed was obtained. Prom M. Jalapa fertUised with pollen 

 of M. longiflora, some plants were raised which produced seed. The 

 flowers were of various colours ; and the roots of these hybrid plants 

 were of enormous size — three and a-half feet in length. The general 

 conclusion to which these experiments led was, that hybrids between 

 species are exactly intermediate, at least in the ease of the Mirabilia. 

 But he arrives at the singular result that hybrids from hybrids do not 

 follow this law, but become infinitely varied and far removed from their 

 original type ; that all hybrid plants are not sterile, and although they 

 may produce seeds but sparingly, yet when the plants from these are 

 crossed with their own parents, the plants resulting are of great 

 fertility. This completely justifies the opinion that no absolute rules 

 for judging of the efifect of an experiment in muling have been yet 

 discovered. 

 The conclusions of Gsertner as to this point are as follows : — 



1 . Various notions have existed, both in the animal and vegetable king- 

 dom, with respect to the degree of influence which the sexes have in the 

 production of hybrids : according to one authority, the male, in animals, 

 giving origin to internal qualities, the female to external ; to another, 

 the former to the cellular system, the latter to the nervous, &c. 

 Amongst plants, the difference of opinion is as great ; but the truth 

 appears to be, that no general rule can be laid down— in Digitalis the 

 influence of the female parent being predominant, in Mcotiana that of 

 the male, and the differences exhibited by individual species are no less 

 decisive against any universal law. And this is no less true as to 

 comparative degrees of fruitfulness. Indeed, the identity of the 

 produce, when the sexes are reversed, is a sufB.cient proof of its non- 

 existence. 



2. When impregnation takes place between two pure species, it is an 

 universal rule, " that the characters of the parents never remain pure 

 and unaltered in the formation of the hybrid." In general every part 

 of the new production is modified, so that it presents a decided differ- 

 ence from either of the parents, though resembling the one more than 

 the other. In no case, however, are anomalous forms generated bearing 

 no resemblance to either. At the same time they are not produced 

 according to mathematical formulse and ratios ; their differences are 

 mingled in unequal proportions. 



3. When the hybrid is impregnated by the original male parent, the 

 result is much the same as in simple hybrids self-fertilised, both in 

 respect of the types produced and the degree of fertility. Various 

 forms are raised from one capsule, and the different individuals'do not 

 present the same degree of susceptibility for impregnation. Different 

 capsules, too, offer very different results. When these mules are in 



