PLATE XXVII 
Fig. i.— Peridermium pyriforme (F. P. 18044) on a trunk of Pinus divaricata, showing 
the form of the peridia before they are ruptured to allow the escape of the seciospores. 
Fig. 2.—A globose gall with Peridermium pyriforme on a trunk of Pinus contorta 
(F. P. 19437), associated with two lesions of Peridermium comptoniae t one near the 
gall and the other 1 inch above it at the base of a branch. 
Fig. 3.— Peridermium pyriforme (F. P. 19429) on a branch of Pinus arizonica showing 
unopened peridia. This branch was 1 inch in diameter and 10 years old. 
