IDENTITY OF PERIDERMIUM FUSIFORME WITH PFRI- 
DERMIUM CEREBRUM 
By George G. Hedgcock, Pathologist , and W. H. Long, Forest Pathologist , Investi¬ 
gations in Forest Pathology , Bureau of Plant Industry 
In this paper the Cronartium stage of the fungus under discussion is 
called Cronartium cerebrum (Peck), n. comb., in place of the C. quercus 
(Brond) Arthur or C. quercuum Miyabe of previous writers. This new 
combination is made because the authors, after a careful examination 
of authentic material of the so-called Cronartium quercus of Europe, find 
that it is not the same fungus as the American Cronartium on oaks 
(j Quercus spp.). 
Peridermium cerebrum , the name for the serial stage of the American 
Cronartium on oaks, was published by Peck in 1873/ and as this is the 
oldest specific name for the fungus the combination Cronartium cere¬ 
brum (Peck) must be used. 
Further evidence that Cronartium quercus of Europe is not Cronartium 
cerebrum of America is found in the following facts: 
(1) Only the uredinial stage of the European fungus has been found. 
If this rust was the same as the American species, then the telial stage 
should certainly have been collected, as it follows closely (within 5 to 10 
days) the uredinial stage. 
(2) No serial stage corresponding to Peridermium cerebrum has been 
reported from the European countries where the so-called Cronartium 
qusrcus is found. 
An investigation of Cronartium cerebrum and of its aecial form 
{Peridermium cerebrum Peck) has been conducted by the senior writer 
for a number of years. As a result of numerous inoculations of 
several species of pines (Pinus spp.) with the telia of this fungus from 
pedigreed cultures inserted in wounds and made under control con¬ 
ditions in the greenhouse at Washington, D. C., it has been found that 
in the pines having two needles, or two to three needles, in the cluster, 
globoid swellings or galls are usually formed on the limbs and twigs, 
while in pines having three needles in the cluster, fusiform, spindle- 
shaped, or oblong swellings are commonly found, which are occasionally 
accompanied by a reversion to the juvenile type of leaves, and by the 
formation of hexenbesen (witches’-brooms). 
In the inoculation experiments mentioned above spheroid swellings 
were commonly formed on Pinus contorta 2 P. edulis , P. densiflora, P. 
divaricata, and P. virginiana; and fusiform swellings, as a rule, were 
formed on P. coulteri , P. ponder os a, P. radiata y and P. sabiniana . 
Since fusiform swellings are produced by Peridermium fusiforme Arthur 
and Kern (PI. XI, fig. 2) and Cronartium cerebrum is found throughout 
the range of this Peridermium, these results suggested that it might be 
identical with Peridermium cerebrum (PI. XI, fig. 1). 
In nature the writers have observed that the spheroid galls are usually 
found on Pinus divaricata , P. clausa, P. echinata , P. glabra, P. resinosa, 
1 Peck, C. H. Descriptions of new species of fungi. In Bui. Buffalo Soc. Nat. Sci., v. i, p. 68. 1873. 
* The nomenclature of trees used in this paper is that of Geo. B. Sudworth, U. S. Dept. Agr., Div. For¬ 
estry Bui. 14, 1897- 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
(247) 
Vol. II, No. 3 
June 15, 1914 
G—24 
