GALLS PRODUCED BY TWO CEDAR RUST FUNGI 247 
On March 19, 1915, several small cedar trees were planted in pots 
in the greenhouse and on April 7 several leaves were found on these 
trees from the surface of which telial horns were developing (PI. XV, 
Fig. 2). One or more were seen to come from the upper surface of 
the infected leaves which were swollen very little or not at all. These 
telial horns resembled those of G. glohosum in shape and color and the 
spore measurements corresponded to those of that species. Inocu- 
lations were made on Crataegus leaves with some of these spores and 
the characteristic aecia of G. globosum developed; thus showing that 
the original determination was correct. Later similar specimens 
were found in nature. Often the infected leaves are yellowed through- 
out a certain portion of their length and the telial horns develop from 
those discolored areas. These tentacles may be found developing 
from any part of the upper surface or side of the leaf. Sections of some 
of these leaves showed them to be completely permeated with mycelium 
which in some cases at least did not extend to the base of the leaf. 
Infection must have undoubtedly occurred in the leaf. 
Having observed that galls of G. globosum sometimes originate 
in the leaf, more careful observations were made to determine if pos- 
sible whether this is always true. A great number of galls of this 
species were examined both during the autumn and winter of 1914 
and 1915 and during the summer of 1915. Hundreds of galls were 
examined and in every case the foliar origin was found. These galls, 
however, usually develop near the base of the leaf and displace a cer- 
tain part of it. As the galls continue to develop the terminal portion 
of the leaf remains attached to the gall and may be found here for 
some time. A careful study of Plate XV, Figs. 3 and 4 will make 
this point clear. A large amount of variation occurs. In some cases 
the gall may grow out from the upper surface of the leaf as do the galls 
caused by G. Juniperi-virginianae, or they may burst out of the side. 
A close inspection of older galls showed in nearly every case the dead 
tip of the original leaf still intact (PI. XV, Figs. 3, 4, 5 and 6). 
The gall grows slowly and is perennial, forming spores for several 
years. In the early stages these galls are nearly mahogany red in 
color as compared with the green color of the minute galls of G. Juni- 
peri-virginianae. The red color gradually changes to grayish brown 
in the older galls. The shape of these galls is more or less globose 
from the beginning and often flattened on the side next to the stem 
(PI. XV, Fig. 4). When the gall becomes older, it displaces the leaf 
