28 HEREDITY, AND THE ORIGIN OF SPECIES. 
masses of cells. If this is so then we may hope to be able 
to duplicate the process in our cultures and call out a pro- 
portion of mutants at our will. The results of experiments 
now in progress seem to lend great favor to this assump- 
tion. 
This view of the case is also favored by the facts offered 
by bud-sports, which have been designated as “vegetative 
mutants, although as shown above, all mutations are essen- 
tially of a vegetative character. In the simplest forms of 
these sports, lateral buds arising generally near the base 
of a shoot develop branches which diverge definitely irom 
the characters of the main shoot, and which usually coin- 
cide with some known form, although this is not always the 
case. Sometimes entirely new forms arise in this mannet 
as in the case of seed-mutants. During the present season 
I have been so fortunate as to have three notable examples 
of bud-sports in the experimental cultures. One of these 
was a basal branch of Oenothera ammophila which sported 
into the characters of O. biennis, and suggesting a possible 
hybrid ancestry with the latter species as one of the parents. 
A second case was one in which a seed-mutant of O. bien- 
mis gave a bud-sport which bore the characters of the at- 
cestral type or the true O. biennis. A third case was one 
in which a plant of one of the numerous types embraced 
in a complex hybrid progeny bore a branch which sported 
in a branch which resembled a sister type. Other ana- 
tomical relations are found. Thus a bud-sport may en 
brace not only a branch, but a portion of the main stem, 
from which it arises, or in other cases it may include a 
section or longitudinal strip along one side of a branch 
even dividing a flower or fruit, while in other cases it may 
be represented by single flowers or fruits scattered indis- 
criminately through an inflorescence. 
It is to be noted that in most if not all of the sectorial 
variations by which a part of a bud bears the divergent 
