238 



TBJ^ BOTANICAL MAGAZINE. 



[Vol. XXVI. No. 308 



near future, we are sure the disease will certainly be observed 

 in the various localities of our countrj-. 



The first indication of this disease is a small, pale yellow 

 speck on the surface of the leaf, and we can see the darker net- 

 ted lines in the tissue of the spot on the affected young leaf, 

 when it is held up against the sun. The speck on a single leaf 

 is variable in number, mostly one or two. It is not clearly 

 limited in outline, irregular in shape, gradually enlarging until 

 it reaches a diameter of 2 or 3 cm., but sometimes until it 

 covers the entire leaf surface. The color of the speck gradual- 

 ly turns into brown and finally into dark brown. The corres- 

 ponding surface on the under side of the leaf assumes at first a 

 gray, dusty appearance. As they mature, the darker reticulat- 

 ed lines in the tissue are at first slightly raised above the level 

 of the leaf-surface, and then by breaking through the epidermis, 

 the characteristic white reticulated hymenium of the fungus is 

 exposed. (Fig. 1) 



The hymenium turns gradually into dark brown color 

 from the central portion toward the periphery- of the speck. 

 Finallv, the affected area of the leaf becomes dry and shrinks up. 



