218 BOTANICAL GAZETTE. | September, 
thin-walled, acutely-angled, polygonal cells. Upon re 
ining a corresponding section taken from an yee ea 
the change which had taken place was found to be as s ~~ 
in fig. 5. The acute angles had disappeared in a grea 
measure and the cell walls wére much thicker. © 
The mycelium of the fungus, Exoascus deformans, whic 
causes these changes, is septate, variable in eerie 
branches irregularly, runs between the cells, and re 5 
with granular protoplasm in which there is considerable oil. 
No haustoria were observed. There was some difficulty in 
finding mycelium running to the surface, but after wie 
sections, various cases were observed in which it was seen to 
ing separated by a septum, form the asci with spores repre- 
sented in fig. 9. As they grow they push up the cuticle We 
finally break through: it: The protoplasm contained in ‘ 
asci rounds off into spores, six or seven usually being foun 
and in some cases eight in each ascus. f: 
To sum up briefly the action of the fungus on the leat: 
1. A marked increase in width and thickness accompa- 
nied by great distortion, {i 
2. Great multiplication of cells, particularly of the Pll 
isade cells and immediately adjacent parenchyma, by cé 
division, 
___3- Thickening of the cell walls and disappearance of the 
intercellular spaces. 
. . i - Vg 
4. Diminution of cell contents which often are almost 0 
wholly wanting 
he 
LANATION OF Plate XIII.— ig. 1, Cross section of a healthy ee 
gad 7 own 
I » 4 spongy parenchym i ge 
the upper surface of an abnormal leaf, a,b cells in process of division, ¢ sre 
jum 
raubairok a. Fig. 3, Cross section of an abnormal leaf showing mycelia 
in different f rms; @ 
i f th 
Fig. 5, Corresponding section of a 
Sections of the upper surfac 
1—8 X 140. Fig. 9 200. 
° 9 ¢ 
al leaf. Figs. 6, 7, 8 and 9, ote : 
of abnormal leaves; o, in fig 6, young ascl. Figs: 
