Bud Varialio}i 125 



2. Maternal inheritance, the male parent contributing only 

 a nucleus to the make-up of the zygote. 



In cases of this sort the source of pollen makes no dilTerence 

 so far as the chlorophyll character is concerned. Consequently, 

 since this maternal inheritance cannot be accounted for by par- 

 thenogenesis in the plants that were used, it has been concluded 

 that the seat of the character in question is in something that the 

 female parent regularly contributes and the male parent never 

 contributes. This idea is supported by certain cytological evidence 

 that suggests the fact that, in some plants at least, the male 

 nucleus is '' stripped clean of its cytoplasm" at the time that it is 

 discharged from the pollen tube into the embryo sac. A similar 

 distinction to that made under i may also be applied here. 



A. The chlorophyll character governed by the distribution of 

 the plastids themselves. 



It follows that pure green and white parts will at times segre- 

 gate out in the variegated plants concerned. Correxs' (5) 

 albomaculata type of Mirabilis is said to be an example of this sort 

 of thing. 



B. The chlorophyll character governed by the distribution of 

 other and finer cytoplasmic elements than the plastids themselves. 



It follows that absolutely pure green and pure white parts will 

 never segregate out, but only relatively paler and relatively greener 

 parts. WiNGE (9) cites some of his own work on a variegated 

 type of Humulus as an example. 



In conclusion it should be said that opinion as to the seat of 

 chlorophyll inheritance is by no means settled. It would doubtless 

 be wise to regard the foregoing classification of W'in'ge's merely 

 as a convenient form in which to arrange the available evidence; 

 other investigators would certainl}' disagree with some of Win'ge's 

 interpretations of the phenomena. 



As an example of a case which can liardly be forced into 

 Winge's classification, An'dersox's (i) green and white variegated 

 race of corn might be cited. Inheritance is strictly maternal, and 

 pure green and white areas segregate out on tlie leaves. Presum- 

 ably then this would fit into Win'ge's class II, 2. A. Hut a care- 

 ful cytological investigation of this material by Randolph (8) has 

 revealed that there can be no sharp segregation among green and 



