WHITE-PINE BLISTER RUST. 5 
found much earlier, and more of it would have been found since 
then. Fischer (40) found the disease in 1915 spreading into western 
and northern Switzerland from without. 
It is generally supposed that Pinus cembra (26, 70, 93, 97, 98, 123) 
is the original pine host of this fungus. Figure 1 shows the distri- 
bution of P. cembra and its variety pumila in Europe and Asia. 
Cronartium ribicola is reported from Asia as follows: In 1879, from 
Fig. 2.— Outline map of the United States, showing the known distribution of Cronartium ribicola and 
C. occidentale in North America to January 1, 1920. Localities for Cronartium occidentale are shown by 
black squares in the Pacific coast and Rocky Mountian regions, the easternmost point being in western 
Kansas. This is where it was found in 1892, but it has not been seen there since. Localities for C. ribicola 
are indicated by double cross hatching and black dots, nearly all being north of the Potomac and Ohio 
Rivers and east of the Mississippi River. Four points in southwestern Minnesota, eastern South Dakota, 
and northern Iowa were found to be due to diseased nursery stock which was shipped in. It is believed 
that the disease now has been eradicated in these outer western localities. The natural distribution of 
the eastern white pine is shown in the large cross-hatched area mostly east of the Mississippi River . The 
cross-hatched areas shown on the western half of the map indicate the known distribution of the western 
white pines. The pinon pines range as far north as southern Idaho but at altitudes different from those 
of the white pines. Cronartium ribicola is limited to the eastern white-pine area and was not known in 
North America until 1906. In most places where now found it has been traced to diseased imported 
white-pine stock. Cronartium occidentale is limited to that part of the western white-pine area in which 
pinon pines are native, where it appears also to be native. The two fungi are separated by a strip of 
prairie country about 500 miles wide. Distribution of the pines furnished by the Forest Service, United 
States Department of Agriculture. Distribution of Cronartium occidentale furnished by Messrs. Bethel 
and Posey, of the Offices of Investigations in Forest Pathology and of Blister-Rust Control, respectively. 
Bolschaja Inja River (131, 161); also from Tomsk and Minusinsk, 
Siberia (131). Quite recently it has been reported from Sakhalin 
Island and from Sapporo, Japan (156). Tulasne (175) in 1854 re- 
ported a Cronartium on Ribes, probably in India. Clinton has 
announced (13) the finding of Cronartium ribicola on dried herbarium 
specimens of Ribes collected by Wilson in the western part of the 
Province of Hupeh, China, in 1900. 
