Bui. 247, U. S. Dept. of Agriculture. 



PLATE I. 



>CIOSPORES OF CRONARTIUM PYRIFORME AND A TWIQ OF PINUS CONTORTA. 



FIG. 1. yEciospores of Cronartium pyrijorme, from the type specimen on Pinus sp. at Albany, 

 N. Y. ( Microphotograph. ) FIG. 2. ^ciospores of Cronartium pyrijorme from Pinus pun- 

 gens, collected near Greenwood Furnace, Pa. (Microphotograph.) These closely resemble 

 the type. FIG. 3. ^Eciospores of Cronartium pyrijorme from Pinus contorta, near Eldorado 

 Springs, Colo., from the same tree as the type of Peridermium betheli (microphotograph), 

 showing the variation in the shape of the spores on this pine from those of the type 

 specimen in figure 1. FIG. 4. A twig of Pinus contorta, showing the secia and peridia of 

 the fungus Peridermium pyrijorme (P. betheli) on a slightly swollen portion. (About natural 

 size.) 



