A DISEASE OF PINES CAUSED BY CRONARTIUM PYRIFORME. 
taken from specimens of the fungus on leaves of Comandra umbel- 
lata obtained by inoculations with seciospores from Pinus pungens 
from Greenwood Furnace, Pa. 
INOCULATION EXPERIMENTS WITH THE FUNGUS. 
Table I gives complete inoculation data for this fungus on Comandra 
umbellata. Successful inoculations were made with seciospores from 
two hosts, Pinus ponderosa and Pinus pungens, collected from three 
widely separated localities in the States of Washington, California, 
and Pennsylvania. In each instance control plants of the same 
species were used, and all remained free from infection. Unsuccessful 
inoculations were made with seciospores from Pinus contorta (Peri- 
dermium betheli) both during 1913 and 1914. In 1914 the failure to 
infect might have been due to the extreme high temperature of the 
greenhouse at the time the inoculation experiments were performed. 
However, the failure for two successive seasons to infect Comandra 
with the seciospores from Pinus contorta may indicate that the rust 
on this host is a different species from Peridermium pyriforme, since 
the shape and size of the seciospores (P. betheli; PL I, fig. 3) from 
Pinus contorta are different from those of the type specimen of this 
rust (PI. I, fig. 1). The writers, in the absence of proof from inocula- 
tions, assume for the present that these morphological differences may 
be due to the host and therefore are not of sufficient importance to 
warrant classifying Peridermium betheli as distinct from P. pyriforme. 
Table I. — Results of inoculations with the seciospores of Cronartium pyriforme. 
^Ecial host, serial num- 
ber, and locality. 
Species inoculated. 
Date of 
inocula- 
tion. 
Results. 
Ure- 
dinia. 
Telia. 
Degree of 
infection. 
Collector. 
Pinus contorta: 
8500, Eldorado 
Comandra umbellata. . 
Comptonia asplenifolia 
Comandra umbellata. . 
1913 
June 18 
...do.... 
June 27 
...do 
No infection. . . 
do 
do... 
Bethel. 
Springs, Colo. 
8500, 1 Eldorado 
Springs, Colo. 
8514, Allenspark, 
Colo. 
Do 
Do. 
Do. 
do . 
Do. 
Pinus ponderosa: 
12467, Wenatchee, 
Wash. 
Do 
Comandra umbellata. . 
do 
1914 
May 27 
May 30 
May 28 
May 29 
May 30 
...do.... 
June 1 
June 2 
...do.... 
June 3 
July 3 
do 
1914 
June 5 
June 9 
June 6 
June 7 
June 10 
June 11 
...do.. 
June 12 
June 13 
...do.. 
1914 
June 28 
July 4 
July 5 
June 30 
July 15 
...do.... 
July 1 
July 4 
July 8 
July 5 
Sparse 2 
do 
do 
Very abun- 
dant. 
do 
do 
Sparse 
Abundant s . . . 
do 
Sparse 
No infection 4 . . 
do 
Fisher. 
Do 
12468, Rocky 
Gulch, Cal. 
Pinus pungens: 
do 
do ...... 
Boyce. 
Hedgcock. 
Do. 
Furnace, Pa. 
do 
Furnace, Pa. 
Do 
15462, Greenwood 
do 
do 
Do. 
Do. 
Furnace, Pa. 
Do 
do 
Do. 
Do... 
...do 
Do. 
Do 
do... 
Do. 
Pinus contorta: 
15550, E 1 d o r a , 
do 
Do. 
Colo. 
Do 
Ribes longiflorum 
Do. 
1 Type of Peridermium betheli.' 
2 Sparse here means less than six sori. 
3 Telia immature. 
i Inoculation made in very hot weather. 
