630 / \ilidity of the Doctrine of Mutation. 



may conclude that this f^reen Dahha had arisen from tlie 

 corresponding double-liowered variety. 



I do not propose to adduce any further instances ; 

 those which I liave given show that varietal characters 

 ma}' chsai)pear in a vegetative way, the original char- 

 acters becoming actixe again. For such a mutation 

 neither the formation of sexual cells nor fertilization 

 is necessary. Therefore the possibility that seed-varia- 

 tions ma}- tiltimately be derived from bud-variations can- 

 not be denied ; 1)ut man}^ more experimental data will have 

 to be collected before a final judgTuent based on a suffi- 

 cient foundation of facts can be given. One of the best 

 methods is that which T have already mentioned, as 

 adopted by Reverixck, of artificially inducing bud-varia- 

 tions by prunuig. 



