Bul. 141, Pt. V, Bureau of Plant Industry, U.S. Dept. of Agriculture. PLaTe IV 
Fic. 3.—PART OF A DISEASED BRANCH OF A CHESTNUT TREE, SHOWING 
TYPICAL PUSTULES AND FORM OF SPORE DISCHARGE IN DAMP WEATHER. 
(Magnified 3 diameters. ) 
