LUTHER BURBANK 
been variation—some few individual clover plants 
have always had the white and black markings. 
“At some time in the history of the plant those 
without the markings have been destroyed, and so, 
responding to this new environment, the markings 
became more and more pronounced until now we 
have not only white triangular markings, but ugly 
black splotches going clear through the leaf. 
“From these markings we can read the history 
of the clover—most of the family having plain 
leaves inherited from an ancestry which found no 
need to protect itself from an enemy—with an 
occasional outcropping of poisonous-looking color 
splotches—the inheritance of scattering environ- 
ments in which self protection was necessary.” 
“Or we might consider the ice-plant, so called, 
which protects itself from the heat of the sun by 
surrounding itself with tiny water drops which 
have the appearance and serve the same purpose 
as icicles; or the wild lettuce, known sometimes 
as the compass plant, which turns its leaves north 
and south so that only their edges are reached 
by the sun; or any of a number of other strange 
protective measures which plants have perfected— 
all manifestations which would be impossible if 
heredity were not an ever present, controlling 
influence. 
[48] 
