CYTOPLASMIC INHERITANCE 185 
white leaves. If the flowers of the green branches are 
self-fertilized, the young plants are green. If the 
flowers of the white branches are self-fertilized, the 
offspring have white leaves and these plants perish 
for want of chlorophyll. From the checkered 
branches the offspring may be green, or checkered, 
or white. 
When a cross is made between the flowers borne 
by branches that are unlike, the inheritance is purely 
maternal. For example, if the pistil of a white 
branch is fertilized with pollen from a pure green 
plant, only white leaved offspring are produced. 
The reciprocal cross, the pistil from a green branch 
fertilized with pollen from a white branch, gives 
only green offspring, and these remain green idl 
all subsequent generations. 
Correns points out that these results can be inter- 
preted if the whitening is due to a sort of disease that 
is carried by the cytoplasm. The egg cytoplasm 
carries over the disease to the next generation. As 
the pollen does not bring in any cytoplasm the 
disease is not transmitted through the male side. 
Baur points out that in several other plants in 
which varieties with leaves marked with white exist, 
as in Melandrium, Antirrhinum, etc., the inheritance 
is strictly Mendelian, for the F, generation is green 
and the F, generation is made up of three greens to 
one marked with white. In these cases the color may 
depend on a chromosomal factor. But there is a 
case in Pelargonium that Baur thinks can not be 
explained in either of the foregoing ways. Here 
