1912] REYNOLDS—PARASITIZED LEAF TISSUE 375 
mesh of rounded cells, stretching from one epidermis to the other. 
The tissue is evidently very easily ruptured, and is seldom complete 
except at the veins and in connection with the fungous spore beds. 
The plants examined were growing in a well-shaded and damp loca- 
tion, and were collected in early summer. 
In the parasitized regions the cells are closely compacted, and 
more or less bound together by the invading mycelium which fills 
the intercellular spaces. Here also the hematoxylin stains much 
more intensely than in the normal tissue. There seems to be some 
hyperplasy of the mesophyll. The epidermis is ruptured by the 
Fics. 1-3.—Cells from leaf of Viola cucullata parasitized by Puccinia Violae: 
fig. 1, two cells showing deformed nuclei and increased number of nucleoli; fig. 2, 
cell showing three nuclei and a few chloroplasts; fig. 3, cell showing three deformed 
spore bed, but the influence of the fungus does not extend far beyond 
this radius. The nuclei, which are not prominent in the normal 
cells, become somewhat enlarged, and increase in number in the 
cells. There are numerous instances where the number is increased 
to two, while some cells were noticed that contained three nuclei. 
The nuclei are also more or less deformed, varying from nearly 
circular in cross-section to oval, oblong, or slightly pear-shaped. 
The chloroplasts seem to be little affected, at least in shape and size, 
by the presence of the parasite. Fig. 1 shows some examples of 
the deformations to the nuclei which are found in the cells near the 
