New YorRK AGRICULTURAL EXPERIMENT STATION. 189 
CIRCUMSTANCES ATTENDING THE DISCOVERY. 
While passing the currant plantation on the Station grounds 
September 26, 1906, the writer observed an unusual appearance 
of the foliage on some plants. Upon plucking one of the leaves 
for examination we were astonished to find the under surface 
yellow with a rust. Even to the unaided eye it was evident that the 
rust belonged to the genus Cronartium and upon microscopic exam- 
ination in the laboratory it proved to be Cronartium ribicola Dietr., 
a currant fungus of common occurrence throughout Europe but 
hitherto unknown in America.” 
The plantation in which the rust was found is one devoted to 
the testing of varieties. It contains about 175 plants and includes 
54 different varieties representing three species; viz., Ribes mgrum, 
R. rubrum, R. aureum. Most of the plants were set in the spring 
of 1903, being transplanted from another plantation about forty 
rods away. The remainder of the plants were set in the spring of 
1904. They varied in height from two to five feet. 
Of the 54 varieties, 48 were more or less rusted while the other 
six were free from rust. The several varieties of black currants, 
Ribes nigrum, were most affected— Monarch, Clipper and Star 
being among the worst and having almost every leaf thickly cov- 
ered with rust. In spite of this severe attack of rust the black 
currants were in full foliage. Some of the red and white varieties, 
R. rubrum, also were severely attacked, but most of them were only 
slightly affected. The plants of this species had already lost a con- 
siderable portion of their foliage from leaf spot, Septoria ribis. 
One variety of R. aureum (Jelly) showed traces of rust. Four 
varieties of R. rubrum (Prince Albert, Gondouin White, Stultz and 
an unknown variety) and two varieties of R. aureum (Crandall and 
Utah Golden) were entirely free from rust. 
*Dr. J. C. Arthur informs us that the only other record of the occurrence 
of this fungus in North America is that of a collection made by E. Bartholo- 
mew on iibes aurcum in Kansas in 1892. This was a solitary collection in 
the uredo stage which remained unrecognized until recently. Bartholomew 
listed the fungus (The Kansas Uredinee. Reprint from Trans. Kans. Acad. 
Science, 16:193. 1897-08. Issued June, 1899), as Uredo confluens Pers., 
but Dr. Arthur, who has examined the specimens, pronounced it the uredo of 
a Cronartium, presumably C. ribicola. 
