in Hybridisation 379 



the dominant characters belong exclusively to one or the 

 other of the original parent plants, it will always make 

 a difference which of the two possesses the majority of 

 dominants. If the pollen parent has the majority, then 

 the selection of forms for further crossing will afford a less 

 degree of certainty than in the reverse case, which must 

 imply a delay in the period of transformation, provided 

 that the experiment is only considered as completed when 

 a form is arrived at which not only exactly resembles the 

 pollen plant in form, but also remains as constant in its 

 progeny. 



Gartner, by the results of these transformation experi- 

 ments, was led to oppose the opinion of those naturalists 

 who dispute the stability of plant species and believe in a 

 continuous evolution of vegetation. He perceives* in the 

 complete transformation of one species into another an 

 indubitable proof that species are fixed within limits beyond 

 which they cannot change. Although this opinion cannot 

 be unconditionally accepted we find on the other hand in 

 Gartner's experiments a noteworthy confirmation of that 

 supposition regarding variability of cultivated plants which 

 has already been expressed. 



Among the experimental species there were cultivated 

 plants, such as Aquilegia atropurpurea and canadensis, 

 Dianthus caryophyllus, chinensis, and japonicus, Nicotiana 

 rustica and paniculata, and hybrids between these species 

 lost none of their stability after four or five generations. 



* [" Es sieht " in the original is clearly a misprint for ' Er sieht."] 



