R. P. Gregory 307 



offspring through the pollen of the male parent. This result con'e- 

 sponds with the similar results obtained by Correns and Baur when 

 crosses were made with flowers taken from the j)ure white (yellowish- 

 white) shoots sometimes bonie by the variegated plants of Mirahilis 

 and Antirrhinum. 



It is to be noticed that crosses between green and yellow plants do 

 not give variegated heterozygotes ; all the oft'spfing are pure for the 

 character borne by the female parent used in the cross. The original 

 variegated plant, from which my variegated race has been bred, appeared 

 in the F„ of a cross between two normal green races, Ivy-leaf and Snow- 

 drift" ; with this exception, variegated plants have invariably been the 

 I >ffspring of a variegated mother. 



As might be expected, the character of the chloroplast is found not 

 to be affected by the presence or absence of anthoeyanic pigment in the 

 cell-sap. The original variegated race was without sap-colour; it has, 

 however, been brought in through matings with other races, and the 

 various combinations of green and of yellow plastids with sap-colour 

 have been obtained in the progeny. 



The variegated character of the stems and leaves, again, is quite 

 independent of the flaked or striped flowers, which result from the 

 development of sap-colour in some cells and its absence from others. 

 The two characters, in fact, stand in contrast to one another, for the 

 flaked character of the flowers is inherited through the male, as well as 

 through the female parent. Here again my results agree with those 

 described by Con-ens in Mirahilis-. 



The plastids of the green and of the pale yelloiu or yellowish-green cells. 



In the fully grown organs of the plant, the plastids contained in any 

 individual cell are, in general, of one kind only; those of the chlorotic 

 cells are smaller than those of the green cells and are of a pale 

 yellowish-green colour, instead of being bright green. The difference 

 between the normal and chlorotic plastids is very strikingly shewn if a 

 variegated plant be examined after exposure to bright sun-light ; the 

 plastids of the normal cells are then packed with rounded or oval 

 starch-grains, while those of the neighbouring chlorotic cells contain 

 only a few small granules of starch (PI. X, iig. 7). The differences in the 



' A description of these races is given in Journ. of Genetics, Vol. i. p. 102, 1911. 

 - Zeitschr.f. Induktive Abst.- u. Vererbungslehre, i. p. 322, 1909. 



