1896] A RUST AND LEAF CASTING OF PINE LEAVES 447 
green longer than other parts when a branch is cut from the tree 
and allowed to die through lack of water. 
As soon as the Coleosporium has ruptured the cortical tissues 
evaporation rapidly increases, until it exceeds that from a cor- 
responding area of healthy tissue. This was proved by the 
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Fic. 1. Diagram showing evaporation from diseased and healthy branches. 
ents: Two 
cobalt Paper test and also by the following experim 
and cut off 
branches, as nearly alike as possible, were secured 
inder water and the cut ends sealed into a flask of nor- 
mal culture solution, so that no water could escape except ° 
through the leaves. Each branch had 206 leaves. The leaves 
v6 one branch were healthy and on the other the & 
"tum had just broken through the diseased areas. saeneben 
a2 ©. June 22, the curves in the accompanying es soe 
show the loss in grams in periods of six hours for ten days, as 
*etermined by a recording balance. The water supply Hig 
®S good as the dry air surrounding the leaves demanded. : 
lack of water was due to the accumulation of resin on the o 
nds of the branches and the development in the same are ws 
Pacterial slimes. The unbroken line represents the loss ag 
“seased branch and the broken line the loss from the healthy 
