PROTOBASIDIOMYCETES 435 



different species. According to Stewart forty-eight out of fifty-four 

 varieties of currants were affected in one plantation in the Geneva 

 outbreak, representing the three species Ribes nigrum, Ribes ru- 

 brum, and Ribes aureum. The only varieties which were free 

 from the fungus in this attack were the following : Prince Albert, 

 Gondouin White, Stultz, and an unknown variety, all of Ribes 

 rubrum, and Crandall and Utah Golden of Ribes aureum. In 

 another plantation where sixteen different species of Ribes were 

 cultivated, only one species, Ribes irriguum, was rusted, but these 

 plantations did not include Ribes nigrum and Ribes rubrum. 



Control. In attempting to control or stamp out this disease, it 

 would seem, with the information at hand, that the only hope 

 would lie in the destruction of one or the other of the two hosts, 

 the currant or pine. It is assumed in this connection that the 

 two host plants are invariably essential to the maintenance of the 

 fungus. Since the fungus appears to be of little importance as a 

 disease of currants, the growers of this fruit evidently will not re- 

 sort to heroic measures, and it will devolve upon foresters to watch 

 closely for the fungus, and if it appears, eliminate the wild species 

 of Ribes from the forest area. 



XXVII. ORANGE RUST OF ASTER AND GOLDEN-ROD 

 Coleosporium Solidaginis (Schw.) Thiim. 



Arthur, J. C., and Kern, F. D. North American Species of Peridermium. 



Built. Torrey Bot. Club 33: 403-438. 1906. 

 Clinton, G. P. Peridermium acicolum, the ^Ecial Stage of Coleosporium 



Solidaginis. Science 25 : 289-290. 1907. 

 Clinton, G. P. Heteroecious Rusts of Connecticut having a Peridermium 



for their yEcial Stage. Conn. Agl. Exp. Sta. Rept. (1907): 369-396. 



pis. 23-32. 



Occurrence. Of the several species of Coleosporium having 

 uredospores and teleutospores on species of Compositas, there is 

 none of such common occurrence throughout North America as 

 the species here discussed. To this species are referred the orange 

 rusts of many species of Aster and Solidago (golden-rod). It in- 

 cludes also as hosts representatives of several other genera, among 

 which is the cultivated aster (Callistephus hortensis). This fungus 

 is by many regarded as identical with a species occurring wide- 

 spread in Europe upon Senecio. 



