182 
Mycologia 
for wide ramification of the rust mycelium. In many instances, 
the uredinia are found to rupture on opposite surfaces of the 
leaves and under such conditions internal uredinia were found in 
the central portion of the mesophyll and occurred as well-devel- 
oped sori with mature spores. In some instances they were ob- 
served to develop adjacent to the bundle tissues. 
The mycelium of the internal sori was abundant and could be 
traced easily to the subepidermal sori. The internal sori appear 
somewhat spherical and the mycelium produces rather a pseudo- 
parenchymatous layer crowding the adjacent cells of the meso- 
phyll. In some sections, pockets or masses of mycelium were 
found which evidently were immature sori. The matured spores 
were similar in size and color to those produced subepidermally. 
Since the development of the uredinial stage is supposed to 
be subepidermal as a rule, this deviation seems worthy of note. 
Such a deviation from the usual method probably represents an 
abnormal rather than a typical condition. In this species the de- 
velopment of the internal uredinia is favored by the abundant 
mycelium from the upper and lower subepidermal sori and by 
the texture of the leaf which allows wide ramification of the rust 
mycelium. 
State College, Pa. 
