DODGE AND ADAMS: PERIDERMIUM CEREBRUM 261 
аз June з. These seedlings were located within two feet of an infec- 
tion at the base of a tree. The first collection of teleutosori was 
made on July 4 at Toms River. We have conducted infection 
experiments with this form of P. Cerebrum in the pine barrens of 
New Jersey and have obtained infections on these two species 
of oak and on О. heterophylla. 
EXPLANATION OF PLATES 4-6 
PLATE 4 
Fic. 1. Peridermium Cerebrum on Pinus virginiana, Bedford, Virginia, April 9, 
1917. Portions of the thin cork layer have been removed at the center and above 
to show the extensive spermatial crust (portions outlined with ink), Natural size. 
About half of the surface shown has the spermatial layer exposed. The wavy out- 
lines marking the boundaries of the exposed areas do not Акита indicate the 
limits of the spermatia-bearing region. The very remarkable extent of the fertile 
layer is brought out strikingly he small unpeeled patches at n center and 
above were at this time, бай, sterile regions, the significance of which is not 
very clear. ыза Rcs we should probably interpret the whole surface of the 
gall as one continuous spermogonial crust. The sterility of certain regions is 
doubtless accidental. 
Fic, 2. n a кыннар m ox of a tree at Lakehurst, New Jersey, May 21, 1916. 
This shows how reads by a series of migrations, giving rise to a number 
of associated galls. The igol point of infection is shown by the oldest dead gall 
at the center. Three other dead galls are seen adjacent to it, above, at the right, 
and below. About the periphery of the canker are six or seven living galls. The 
galls were outlined with ink on the photograph. Tree 18 inches in diameter. 
PLATE 5. 
Fic. т. Peridermium Cerebrum on Time rigida, Toms River, New Jersey, 1916. 
The pene type of infection in this region causes а characteristic bending of the 
trunk. Infection аа at the left ser spread peripherally to the right. The 
galls at the pu and center are dead. The one at the extreme right is living. Tree 
IO inches in diameter at this point. (Cross-section of this specimen is shcwn in 
PLATE Ó я 
Е eridermium Cerebrum on Pinus Анн Toms River, New Jersey, 
June, а а at base of tree about 12 es in diameter. The infection 
spread peripherally. The dark area just at the roi of the center is dead, but 
the bark still adheres. The other lobes of the gall are producing aecidiospores 
PLATE 6 
Cross-section of the infected region of a trunk ten inches in diameter s 
surface view of the same specimen is shown in PLATE 4, FIG. I). алети beginnin, 
at about third year, as shown by death of the wood in the rig central part, Se 
spread peripherally in both directions. The first gall has ме Газни owing 
to decay. On either side can be seen the remains of other galls that were formed 
with the first migrations of the fungus. At the left are two living galls. 
