Vegetative Mutations. 615 



the evidence bearin*^" on ihem. Most of the later writers 

 liave agreed with him. Delage opposes tlie \ iew that 

 fertihzation is the sole cause of variability, partly <»n 

 the ground of the existence of bud-variations, ])artly 

 because nothing new is produced in fertilization, in which 

 nothing more occurs than a recombination of heritable 

 characters already present.^ Savastano gives many rea- 

 sons, derived chiefly from the study of woody plants, in 

 su])port of the view that varieties usually arise from seeds 

 and more rarely from buds.- Bailey, on the other hand, 

 lays greater stress on bud-\ariations. According to him 

 bi-sexual reproduction is not a condition of variability, 

 since many new varieties have arisen by vegetative means, 

 such as several sorts of pine-apples, bananas, straw^berries, 

 apples, weeping willows, etc.^ 



Kassowitz goes furthest in this direction when he 

 says :^ ^'Even if there had never been any sexual rei)ro- 

 duction, our earth would be peopled by beings diltering 

 widely from one another in their characters and in their 

 functions ; and there is no ground for the assumption that 

 the differences between the most widely separated forms 

 would have been any less without this (i. e., sexual re- 

 production) than it actually is." 



The conclusion from this all too brief historical sur- 

 vey is that the importance of vegetative mutations is 

 gradually obtaining wider recognition, whilst the attempt 

 to associate species-forming variability with fertilization 

 is coming to be regarded with less and less favor. 



' Y. Delage, L'licredite, 1895, p. 283. 



'L. S.w.ASTANo, La Varicta in arhoriciiltura. Annali d. R. Sciiola 

 Sup. d'Agricoltura in Portici, 1899. I. 2. p. 63 and clscwheri-. 



'L. H. Bailey, TJie Plant Judh-idnaJ !n the Lii^lif of Evolution, 

 Science, 1897. 



* Ma.x. Kassowitz. AUs,cmcinc Biologic, II, 1S99. p. 247. 



