On the Relationship of Chrysomyxa 



expansa Diet, to JPeridermium 



Phece-hondoensis D i et. 



By 

 Kingo Miyabe. 



Up to the present time, Chrysomyxa expansa Diet. (5) has 

 only been known to infect the species of Rhododendron belonging 

 to the Section Eurhododendron (10, 13). The species is nearly 

 related to Chrysomyxa himalensis Barcl. (1, 2), from which it 

 differs by its sori being strictly foliicolous and more or less 

 closely and evenl} r arranged in a roundish discolored spot. 



The type specimen is on Rhododendron japonicum Schneid. 

 (13) {R. Metternichii S. et Z. (10) , R. Hymenanthes Mak. (9)) 

 collected by Prof. S. Kusano in Xikko in the latter part of May, 

 1899. The telentospore sori were then almost fully developed, 

 although none were seen to have germinated. In the same 

 locality, in the summer of 1900, Profs. G. Yamada and J. Han- 

 zawa collected the same fungus on R. hrachycarpum G. Don. 

 (10, 13). 



In Hokkaido, Rhododendron hrachycarpum is very widely 

 distributed, extending even to the Islands of Kunajiri and Eto- 

 rofu. And with the host, C. expansa seems also to have a 

 wide distribution. So far, however, we have received the speci- 

 mens only from the Provinces of Kushiro, Tokachi, Hidaka and 

 Ishikari. In the Prov. of Kushiro, the late Mr. Takiya Kawa- 

 kami collected the fungus on Mt. Meakan at the altitude of 

 1000 ft. in the latter part of July in 1897. The spores had 

 already germinated, the sori becoming fused together into irre- 

 gular masses, some showing a netted appearance. In the autumn 



