Cedar-Apple ( Gy mno sporangium Macropus), 267 
♦ 
places the walls of the closely packed and interwoven my- 
celial filaments often fuse one with another, and, the adjacent 
parts becoming absorbed, form a pseudo-parenchyma. From 
these dense collections of mycelium long hyaline filaments 
are given off, and, together with the spores which they bear 
upon their outer ends, form the spore-masses, Fig. 1, c. The 
greater portion of the central part of these masses is com- 
posed of spore-bearing filaments, and the spores are mostly 
at or near the surface of the masses. The spore-bearing fila- 
ments form the so-called ‘ gelatinous 5 part of the spore-mass. 
Each filament is a tube whose lumen has become nearly 
obliterated by the thickening of the walls. When placed in 
water the walls of these filaments swell rapidly, both in length 
and thickness, and their walls adhere together until they all 
appear to form a solid, almost homogeneous mass ; but if 
this mass be then treated with absolute alcohol, it is shrunken 
until the individual filaments stand out distinctly, as shown 
in Fig. 8. These facts are easily demonstrated by cutting 
longitudinal sections of spore-masses and treating alternately 
with water and alcohol while watching them under the micro- 
scope. 
The spores are two-celled and their contents are very 
granular. Their walls are thick and definite, as is commonly 
the case with the walls of teleuto-spores, Fig. 7. 
All drawings, except figures 1 and 2, were made with a 
camera. In this investigation I found the use of reagents 
generally of little assistance, but derived better results from 
material gathered and preserved in alcohol than from fresh 
material used. 
Summarizing briefly the changes which take place in the 
leaf as the result of the attack of the fungus : 
1. The most striking is the great multiplication of cells, and 
their generally enlarged size. 
2. The cell-walls are thicker, and their deportment towards 
reagents is much more like that of the fungus-filaments than 
that of the cells of the normal leaf. 
3. The fibrovascular system is developed until it assumes 
U 
