1912] REY NOLDS—PARASITIZED LEAF TISSUE 379 
same width as those cells. This palisade occupies half the thick- 
ness of the leaf. The sponge cells are loosely connected and have 
large air chambers scattered among them. The tree, from which 
the diseased leaves were taken, was growing in a thicket, and about 
50 feet from a Juniperus tree. 
The portion of the leaf which is parasitized is about twice as 
thick as the normal tissue. This thickening is due to two factors, 
the hypertrophy of the sponge tissue, and the presence of masses 
of mycelium. The palisade cells are least affected. The cells in 
the upper layer are shortened until they are about the length of the 
cells in the second layer. The space thus left between the upper 
epidermis and the palisade cells is occupied by mycelium from which 
the pycnia are developed. The upper epidermis is puffed up and 
ruptured, the cells are nearly collapsed, the 
walls are changed to a brown color, and the 
cuticle is mostly destroyed. The paren- 
chyma cell walls seem to remain about ya eee 
normal. The sponge cells are enlarged gon oe of Pyrus Malus 
to twice or thrice their normal diameters, parasitized by Gymno- 
and the spaces between are filled with the  ‘era"sium, showmg: no 
heavily stained mycelium. The nuclei of carne oat a 
yellowish granules. 
the sponge cells are the first to show the 
effects of the presence of the fungus by becoming rather larger 
than they are normally. They are not, however, otherwise materi- 
_ ally changed. Many cells are partially filled with a yellow, granular 
deposit (fig. 7)." 
8. SMILACINA RACEMOSA (L.) Desf., parasitized by Phyllosticta 
cruenta (Fr.) Kicks.—The leaf of Smilacina is rather simple in 
structure. The upper epidermis has relatively large oblong cells, 
interspersed at intervals with short cubical cells. The lower epi- 
dermis has smaller and usually more regular cells. Between these 
two layers is a rather loose parenchyma with large air spaces, and 
with the larger number of cells close to the upper epidermis. The 
plants collected were growing at the side of a road through the 
woods, where the light was rather weak and there was abundant 
moisture. 
* Fig. 7 was drawn with a }-inch objective, and hence is not on the same scale as 
the other patio 
