No. 603] 



BUD-VARIATION 



factory solution of this problem from three different lines 

 of research, pedigree cultures, graft-hybrids and cell- 

 studies. 



It is a noteworthy fact that the character of the progeny 

 produced sexually by bud-variations has been studied in 

 a comparatively few cases, and in most of these instances 

 self-pollinations were not made. Nevertheless Cramer 

 believes the following conclusions are justified: 



1. In a vegetative Mendelization, of the progeny of a 

 branch with the positive character 75 per cent, have the 

 character and 25 per cent, are without it, while the prog- 

 eny of a branch without the character all lack it. 



2. In a vegetative "Zwischenrasse" by which he gen- 

 erally means a variegated race, of the progeny of each 

 type (original and variant), a part retain and a part lack 

 the character, the percentage being variable. 



3. In a vegetative mutation, by which he means any 

 change not a ''Zwischenrasse" and which did not appear 

 to him to be Mendelian in type, of the progeny of a branch 

 retaining the positive character, either all possessed it or 

 a part were with and a part without it, while the progeny 

 of a branch without the character were all of the same 

 type. 



If we allow for some deviation due to cross-pollination, 

 I believe that Cramer's records support this view, and 

 that modern genetic research suggests the interpretation. 



In the first place, the *'Zwischenrasse" are evidently 

 of the type studied principally by Correns and by Baur 

 in sexually reproducing races. They are due to chro- 

 matophore changes, and in many cases at least are not 

 the result of nuclear activity. This being true, one would 

 expect in neither asexual nor sexual reproduction the 

 same type of inhentance for variegated races that obtains 

 for other types of variation. Inheritance will parallel 

 cytoplasmic rather than nuclear distribution; an expecta- 

 tion apparently realized for l)ot1i types of roprorlnction. 



Omitting the^Zwischenrasson"' theroforo, weliavc two 

 phenomena to explain, both of whicli are similar to caseF? 

 of inheritance in sexual reproduction where chromatin 



