Journal of Mycology 
VOLUME 12-MAY 1906 
TABLE OF CONTENTS 
Shear—P eridermium cerebrum Peck and Cronartium Quercuum 
(Berk). ... 89 
Morgan — North American Species of Heliomyces. 92 
Ricker — Second Supplement to New Genera — ( Concluded). 95 
Kellerman — Index to North American Mycology. 112 
Kellerman — Notes from Mycological Literature, XIX. 128 
Editor’s Notes. . 136 
PERiDERMIUM CEREBRUM PECK AND CRONARTIUM 
QUERCUUM (BERK.)* 
C. L. SHEAR. 
The recent work of Klebahn, * 1 Ed. Fischer, 3 and Shirai 2 on 
certain species of Peridermium and their relation to Cronartium 
naturally suggests the probable connection of our American spe¬ 
cies. The common occurrence of P. cerebrum on trunks and 
branches of Pinus Virginiana about Washington and also the 
abundance of Cronartium Quercuum (Berk.) on oaks in the same 
vicinity led to the suspicion that a connection existed between 
these two forms. 
With a view of obtaining some more definite light on the 
subject, some outdoor inoculations were made in the spring of 
1902 by applying the aecidiospores of Peridermium cerebrum to 
the leaves of Quercus Prinus, Q. alba and Q. coccinca. The inocu¬ 
lations were made just about sundown on the evening of May 1, 
twelve marked leaves being used in each case. No infection took 
place in the case of Q. Prinus and Q. alba, which are usually 
entirely free from the fungus in this vicinity. 
On May 12 uredo sori were found on the under surface of 
the infected leaves of Q. coccinea, as follows: 
♦Read before the American Mycological Society. New Orleans, Jam. 
1, 1906. 
1 Deutsch Bot. Gesell. 8, 1890, 61, and later papers. 
2 Beitrage Krypt. Schweiz. 1, 1898, 90, and elsewhere. 
3 Bot. Mag. 13, 1899, 74. 
