2 BULLETIN 247, U. S. DEPARTMENT OE AGRICULTURE. 
new species, Peridermium betheli (6). The type material P. pyri- 
forme was not accessible at the time the article was prepared, as all 
of Peck's specimens were packed up and in transit from the old to 
the new quarters of the New York State Museum. The writers there- 
fore had to depend upon Arthur and Kern's published statement con- 
cerning this species (1, p. 420). The spore measurements also of the 
typical P. pyriforme did not correspond, since the length of spores of 
the eastern species as given by Peck in his original description was 
too great. While this article by the writers (6) was in press, Arthur 
and Kern published an article (2) in which they discarded their earlier 
interpretation of P. pyriforme and admitted that there is a species of 
Peridermium with typical ''pyriform, obovate, or oblong-pyriform 
spores," just as Peck had originally described it in 1875 (10), and 
that their original assignment of P. pyriforme Peck to what is now 
known as P. comptoniae was an error. They also suggested that the 
alternate stages of this Peridermium would probably be found on 
species of Comandra. 
Orton and Adams (9), in 1914, published an article on Peridermium 
from Pennsylvania, in which they discussed Peridermium comptoniae 
and P. pyriforme. They described the finding of a caulicolous species 
of Peridermium at Charteroak, Huntingdon County, Pa., on the 
trunks of Pinus pungens, which proved to be the true Peridermium 
pyriforme of Peck. Subsequently Cronartium comandrae was found 
within 40 feet of the infected pines and the conclusion reached that 
this Cronartium is the alternate stage of Peridermium pyriforme. 
They also state that P. betheli is probably a synonym of P. pyriforme. 
In May, 1914, Arthur and Kern in a general discussion of the North 
American species of Peridermium inhabiting pines (3) gave the syn- 
onymy of P. pyriforme, a technical description, and an explanation 
of their change of opinion regarding the species. 
In June, 1914, the writers published culture data (8) showing that 
successful sowings of the ssciospores of Peridermium pyriforme had 
heen made on Comandra umbellata, thus completing the life cycle of 
this interesting rust and proving that its alternate stage was the 
Cronartium found on Comandra. 
MORPHOLOGY OF THE FUNGUS. 
The macroscopic characters of Peridermium pyriforme are practi- 
cally identical on all the hosts examined by the writers, but there 
are some differences in the microscopic characters, especially in the 
shape and size of the seciospores. This difference in size and shape 
of the spores may be due to the influence of the secial host; that is, 
they may vary according to the species of Pinus which the Perider- 
rium inhabits. In specimens of the rust on Pinus contorta (PL I, 
