33 2 
Journal of Agricultural Research 
Vol. VIII, No -9 
SUMMARY 
(1) All four types of rust sori have been found developing internally 
in the host-plant tissue, producing spores which appear quite normal 
and which fill intercellular spaces or force aside the softer tissue. 
(2) The fact that Cronartium ribicola Fisher produces internal telia 
is here reported for the first time. These telia form spores inside the 
petioles of species of Ribes, chiefly in the pith and pericycle region. 
(3) Internal sori should be regarded as rather common teratological 
phenomena. 
LITERATURE CITED 
(1) Adams, J. F. 
1916. Internal uredinia. In Mycologia, v. 8, no. 3, p. 181^-182, pi. 186. 
(2) BoixEY, H. L., and Pritchard, F. J. 
1905. Internal infection of the wheat grain by rust—A new observation. In 
Science, n. s. v. 22, no. 559, p. 343“344- 
(3) Fromme, F. D. 
1912. Sexual fusions in the flax rust. In Bui. Torrey Bot. Club., v. 39, no. 3, 
p. 113-131, pi. 8-9. 
( 4 ) -• 
1914. The morphology and cytology of the aecidium cup. In Bot. Gaz., v. 58, 
no. 1, p. 1-35, 8 fig., pi. 1-2. 
(5) Pritchard, F. J. 
1911. A preliminary report on the yearly origin and dissemination of Puccinia 
graminis. In Bot. Gaz., v. 52, no. 3, p. 169-192. pi. 4. 
Cites W. J. Smith (p. 173). 
( 6 ) . -. 
1911. The wintering of Puccinia graminis tritici E. and H. and the infection 
of wheat thru the seed. In Phytopathology, v. 1, no. 5, p. 150-154. 2 
fig., pi. 22. 
(7) Wolf, F. A. 
1913. Internal aecia. In Mycologia, v. 5, no. 6, p. 303-304, pi. in. 
