Jan. »4, 1916 
Peridermium filamentosum 
783 
On May 17, 1915, aeciospores from the “hip canker” of Pinus contorta 
from Haugan, Mont., were sown on two plants of CastUleja miniata under 
control conditions in the greenhouse at Missoula. On June 3 uredospores 
were present on the leaves. The teliospores appeared June 14. The two 
control plants remained healthy. The Cronartium was identical with 
that previously produced by the inoculations on CastUleja miniata with 
aeciospores from the Peridermium on the 2-year-old seedlings of Pinus 
ponderosa . This demonstrates the identity of the “hip canker” Peri¬ 
dermium with Peridermium filamentosum . 
The following cultural data show that the gall-forming Peridermium 
of the lodgepole pine is likewise identical with Peridermium filamentosum. 
On May 25, 1915, aeciospores from the gall-forming Peridermium on 
branches of lodgepole pine were sown by the writers on three plants of 
CastUleja miniata under control conditions in the greenhouse. By June 
11, 1915, uredospores had developed on the leaves, telia and sporidia. 
being produced 10 days later. The two control plants remained healthy. 
Check experiments carried on at the field camp at Priest River, Idaho, 
gave similar positive results. Six plants of CastUleja miniata were 
inoculated and gave positive results. All three control plants remained 
healthy. 
Cultures, under control, made both in the greenhouse and in the field, 
on CastUleja miniata with aeciospores taken from the blister rust on the 
lodgepole pine commonly known as Peridermium stalactiforme A. and K., 
have produced Cronartium coleosporioides (D. and H.) Arthur. Two 
plants of CastUleja miniata were inoculated and two control plants set 
aside. Both inoculated and control plants were covered with oiled- 
paper bags. The inoculated plants gave positive results and the con¬ 
trols remained healthy. This confirms the results of Meinecke 1 and the 
conclusions of Arthur and Kern 2 and places Peridermium stalactiforme 
without further doubt under Peridermium filamentosum . 
The absence of oaks (Quercus spp.), the alternate hosts of Peridermium 
harknessii 3 and Peridermium cerebrum , from this region where the species 
of Peridermium on the lodgepole pine is so prolific, the characteristic fila¬ 
mentous processes in the aecia of the various forms of Peridermium appear¬ 
ing on the lodgepole pine, and the inoculation experiments successfully 
conducted on CastUleja miniata , all exclude the possibility of this fungus 
being other than Peridermium filamentosum. 
The yellow-pine seedlings in the nursery were free from traumatic 
injuries. This is explained by the fact that they had remained in the 
same bed since germination and thus were not exposed to the in jury from 
transplanting. All seedlings showing slight corrugations or blisterings 
of the lower stems gave no evidence of mechanical injury, but they 
1 Meinecke, E. P. Op. cit. 
2 Arthur, J. C., and Kern, F. D. Op. cit. 
8 Hedgcock, G. G. Notes on some western Urediniae which attack forest trees. II. In Phytopathology, 
v. 3, no. 1, p. 15-17- 1913- 
