Missouri Botanical 
Garden Bulletin 
Vol. III St. Louis, Mo., December, 1915 No. 12 
VARIEGATED LEAVES 
The majority of mature plants are dependent entirely 
upon their leaves for the formation of organic matter from 
inorganic—a function which, with the exception of some of 
the bacteria, is confined exclusively to the substance called 
chlorophyll, which gives the green color to the leaf. 
The tremendous importance of this ability to convert 
the simple inorganic substances, carbonic acid and water, 
into a complicated organic substance readily trans- 
formed into a carbohydrate, like starch, makes chlorophyll 
one of the most fundamental products of nature. Conse- 
quently, any condition which interferes with the normal 
formation of “leaf green’ is of serious import to the plant, 
and the occurrence of white or variegated leaves is an inter- 
esting phenomenon, worthy of study. It is a well-known 
fact that, with very few exceptions, sunlight is necessary for 
the production of chlorophyll, and plants grown in the dark 
are always yellowish, due to the more or less complete ab- 
sence of this green substance. It is not this type of bleach- 
ing, however, which is to be discussed, but rather the mot- 
tling, striping, white edging, etc., so commonly seen in the 
leaves of cultivated plants growing under normal conditions. 
Most of these variegated varieties have originated from 
cuttings made from branches showing this peculiarity, or 
from plants which have suddenly, for no particular reason, so 
far as the ordinary. observer could detect, produced leaves 
with white markings. A visitor to the Garden might very 
roperly ask what has caused a plant, normally green, to 
ievelon conspicuous yellow or white areas, although growing 
in direct sunlight. Why is it that some plants have branches 
with green foliage, while other branches bear variegated 
leaves? Why is a leaf spaced with yellowish or white 
patches instead of being of one color? While all of these 
questions cannot be answered with absolute certainty, careful 
study has developed some interesting facts concerning this 
variegation; or chlorosis, as it is technically termed. 
(157) 
