4 BULLETIN 1186, U. S. DEPARTMENT OF AGRICULTURE. 
“pos ie lh ea 
cembra infected in the countries visited, although a single instance 
of its occurrence on this species is reported from Switzerland (37). 
Besides occurring on Pinus cembra and P. strobus, it has been found 
(and seen by the writer, except as otherwise noted) in Europe on 
other species as follows: P. ayacahuite Ehrenb. (British Isles and 
Belgium), P. excels (Denmark, 36, p. 312), P. flexilis (Belgium, 
France, Germany (42), Norway, Sweden), P. koraiensis (Sweden), | 
P. lambertiana (Belgium, British Isles, France, Germany (42)° | 
P. monticola (Belgium, British Isles, Germany (42)), P. pentaphylla 
(British Isles),° and P. peuce (Belgium,’ Germany (42)). 
Inoculation experiments successfully conducted by many European 
investigators show that all five-leaved pines and Ribes tested are 
susceptible to the fungus, though varying greatly in their degree of 
susceptibility. The experiments also prove the independence of the 
two forms Peridermium pint and P. strobi. It is worthy of mention 
at this point that the earliest known Cronartium on Ribes, though 
not C. ribicola, was collected by Jacquemont (43), the French ex- 
plorer, in India in 1830 and determined by Leveille as Cronartium 
asclepiadeum.® This is particularly significant, since in 1914 a bark- 
inhabiting Peridermium was found on the Himalayan white pine 
(Pinus excelsa) and sent to the Mycological Bureau at Pusa, India. 
Dr. E. J. Butler, of the Bureau of Mycology at Kew, England, kindly 
forwarded a specimen of the Peridermium to the writer, who sent it 
to Dr. R. H. Colley, of the Office of Forest Pathology, for deter, 
mination. He found it to be distinctly different from Cronartium 
ribicola. 
CURRANTS AND GOOSEBERRIES. 
Herbariums in the botanical museums were carefully scanned for 
Ribes species serving as hosts for Cronartium ribicola and for the 
localities and dates of occurrence. A total of 29 species was recorded, 
covering all the western European countries. Of the common Ribes, 
the most readily infected is ntgrum (41), while grossularia and 
rubrum are less susceptible. The writer found the first-mentioned 
species, but not the last-mentioned, infected in Europe. In the Vil- 
morin Arboretum at Nogent sur Vernisson, Loiret, France, 35 species 
were examined, and only two were found infected, namely, Ribes _ 
caucasicum and Ribes propinquum, both of which were badly dis- — 
eased. European foresters regard P7bes nigrum as the most danger- 
ous species and consider other European Ribes as of little consequence 
as agents for harboring the white-pine blister rust. 
CURRANTS AND GOOSEBERRIES KNOWN TO BE SUSCEPTIBLE. ; 
The list of varieties shown in Table 1 includes all infected species _ 
of Ribes seen by the writer in herbariums and elsewhere in Kurope,as _ 
well as those observed by a correspondent, Prof. O. Juel, in 1920, in — 
the Botanical Gardens at Upsala, Sweden; but undoubtedly other — 
host species exist in other European collections. 
5 Correspondence with Professor Von Tubeuf, 
6 Reported by the Forestry Commission for Scotland. 
7 Reported as having occurred at Groenendael, Belgium. é 
8 Specimen in Cryptogamic Herbarium, Botanical Museum, Paris. 
