M. Cli. Naudin o?^ Hyhridity in Plants. 



229 



fS ) Oil the return of Hybrids to the specijic forms of the pro- 

 ducing species. What is the cause luhich determines this 

 return ? 



In every hybrid which I have examined, the second 

 generation presented changes of aspect, and a manifest 

 tendency to return to the forms of the producing species, 

 and that under such conditions that it was impossible for 

 the pollen of those species to have concurred in bringing 

 them back. We have seen striking examples in Primula 

 officinali-gvandifloTa^ in all the hybrids of Datura Stra- 

 monium, D. Meteloido-Metel, the mutual hybrids oi Nicotiana 

 angustifolia and macropliylla, N. loersica, and Langsdorffii, 

 Petunia violacea and nyciaginijiora, in Luffa acutangido- 

 cylindrica, and still more in Linaria purpweo-vidgaris. 

 Among many of these hybrids, from the second generation, 

 a complete return to one or other, or even both, of the 

 two parent species has been seen, and approaching them in 

 different degrees ; among many also we have observed 

 forms continuing intermediate, whilst simultaneously other 

 specimens of the very same production have effected the 

 return of which I am about to speak. Further, we have 

 stated in some cases {Linaria purpureo-vidgaris) that, in 

 the third and fourth generation, true retrogression towards 

 the hybrid form takes place ; and sometimes even we have 

 seen individuals of a plant to all appearance wholly returned 

 to one of the two species, which seemed to revert almost 

 entirely into the opposite species. 



All these facts are naturally explained by the disjunction 

 of the two specijic essences in the pollen and ovides of the 

 hybrid. A hybrid is an individual in which two different 

 essences are found united, each having its particular mode 

 of vegetation and finality, which are mutually opposed, and 

 are constantly striving to disengage themselves from one 

 another. Are these two essences intimately blended ? Do 

 they reciprocally penetrate evefy part, so that each particle 

 of the hybrid plant, however minute or divided, contains 

 equal portions of both ? 



It maybe so in the embryo and first stages of the develop- 

 ment of the hybrid ; but it' seems to me more probable that 



NEW SERIES. VOL. XIX. NO. II. APRIL 1864. 2 G 



