REPORT OF THE BOTANIST. 
A PARASITE UPON CARNATION RUST. * 
Freperick H. BLoDGETT. 
SUMMARY. 
‘The growers of carnations in America have been troubled since 
1891 with a disease known as rust, Uromyces caryophyllinus (S.) 
Schroet. No marked success has followed the numerous attempts 
to check its development. Recently a natural check was noticed 
infesting the pustules of rust; this was the fungus, Darluca filum 
(Biy.) Cast. Possibly some benefit may be derived from artificially 
introducing this fungus into carnation houses, but it is not suffi- 
ciently abundant to be of great assistance in natural conditions. 
INTRODUCTION. 
The carnation industry employs many men and a large amount 
of capital and tends to concentrate about the large cities. Many 
varieties are grown, some healthy and robust, others diseased and 
sickly when similarly treated. One of the most common diseases 
is the rust, which manifests itself by producing blisters upon the 
leaves and stems from which a fine orange-brown powder escapes. 
The powder is formed of the spores of the fungus Uromyces cary- 
ophyliinus (S.) Schroet. There is no satisfactory method of con- 
trolling the rust when once introduced. 
On many rusts there is present in the pustules a fungus which 
attacks the rust plant and lives upon it as the rust lives upon the 
host. This fungus, Darluca filum (Biy.) Cast., has been recently 
*Reprint of Bulletin No. 175. 
