318 BOTANICAL GAZETTE [NOVEMBER 
up on drying, soon after the ripening of the ecidia. The epi- 
dermal and hypodermal cells are lignified. 
The mesophyll is made up of a mass of large, irregular cells, 
with large intercellular spaces. There is no differentiation into 
palisade tissue and spongy parenchyma. The fungus mycelium 
is found in all the cells and intercellular spaces. The two resin 
canals are also present in the diseased leaf. Their epithelial 
cells are usually larger and more irregular than the normal. 
The strengthening cells are not thickened, hence the resin canals 
become irregular in form and size, and often lose their identity 
in older leaves. 
The endoderm is seldom distinguishable as such, its cells 
forming no ring. 
The two lignified parenchyma areas of the pericycle are well 
defined, especially at the basal portion of the leaf. The trans- 
fusion tissue is nearly always present, often in one to three small 
areas on the dorsal side of the phloem part of the vascular bun- 
dle. In well developed leaves, especially in sections made near 
the base, the transfusion tissue fills up more than one-half of the 
pericycle. It is unlike the pitted parenchyma of the normal 
pericycle, in that its cell walls have simple as well as bordered pits. 
The cells are also irregular in form, and often thicker walled. 
The bordered pits are often twice the size of the normal (jg. 5 ). 
The non-pitted parenchyma of the pericycle differs from that 
in the normal, in that its cells are always thicker walled and 
usually larger, but fewer in number. The two or three layers of 
cells, separating the bifurcated bundle, as well as the cells of we 
wedge shaped portion on the ventral side of the bundle, consist 
mainly of thick walled fibrous cells, which are seldom found 
thickened in the normal leaves (fig. 6). 
The vascular bundle is double excepting at the base and apex 
of the diseased leaf. _The phloem cells are larger, and the 
cells thicker walled, than in the normal. They are not arranged 
are not) 
as regularly in rows, and the rows, when distinguishable, ' 
separated by medullary rays, these being absent in the dis 
leaves. 
xylem 
