Bud Variation 123 



mcchaaism for segregation is involved as that of the reduction 

 division, at least the segregation is effected with some regularity. 

 3. Cytoplasmic segrkgation.— Numerous cases of apparent 

 segregation of cytoplasmic elements have been i)rovi(led in i)lants. 

 All of them involve visible effects on chlorophyll and all show non- 

 Mendelian inheritance. (Cytoplasmic segregation is the conclud- 

 ing item in Emerson's classification of bud variation. In order 

 better to bring out the relationship between cytoplasmic segrega- 

 tion and certain other plant phenomena, this item will be taken 

 up as a part of the following classification [from Winge 9] of cases 

 of chlorophyll inheritance.) 



Chlorophyll Lvheritaxce 



I. IMendelian inheritance, the characters being "carried in" 

 the nucleus. 



Quite an array of cases of chlorophyll deficiency have been 

 found to be inherited according to the normal JMendelian mecha- 

 nism. In this class have been noted albino, pale green, yellow, and 

 variegated types which are (usually) inherited as simple Mendelian 

 lecessives to the normal green condition. 



II. Non-Mendelian inheritance, the characters being carried 

 in some extra-nuclear portion of the gametes (Emerson's cyto- 

 plasmic segregation). 



I. Biparental inheritance, the male as well as the female par- 

 ent contributing (presumably) both cytoplasm and plastids to the 

 zygote. 



A. The chlorophyll character governed by the distribution of 

 the plastids themselves. 



An example of this type of thing is provided by the work of 

 Baur (2) on certain types of Pelargonium, where the following 

 behavior has been noted. If a white-leaved plant (white-leaved 

 branch, see below) and a normal green-leaved plant are crossed 

 (either way), the resulting hybrid illustrates what has been called 

 by some ''particulate inheritance"; that is. the hybrid is varie- 

 gated, showing irregular patches of green and white. If one of 

 these white patches completely includes a bud. there will probably 

 be produced by that bud a completely white branch. The flowers 

 of this branch, when self-fertilized, give rise through their seeds 



