kern: JAPANESE SPECIES OF GYMNOSPORANGIUM 25 1 



another species of Heyderia is known in the Orient makes the 

 suggestion worthy of consideration. Altogether there have been 

 three aecidioid aecia described on pomaceous hosts. These are 

 interesting because the host relation calls for a Gymno sporangium 

 connection, whereas the structure would not appear to do since 

 most Gymno sporangium species produce roestelioid aecia. There 

 can, however, be no question about the connection of G. Blas- 

 daleanum, which possibly includes the Japanese form, with 

 aecidioid forms on various Pomaceae. The third form is Aecidium 

 Sorbi Arth., from the northern Pacific Coast region of North 

 America. Several years ago the WTiter^ predicted the relationship 

 of this with Uredo 7iootkatensis Trelease on Chamaecyparis nootka- 

 tensis. At that time such a prediction was quite novel since it 

 was not certain that the Uredo nootkatensis represented a Gymno- 

 sporangium. Since that time Arthur- has reported the discovery 

 of telia in this form. 



There is also additional field evidence that it is related to 

 Aecidium Sorbi as predicted. This is an especially interesting 

 species since it is the only one in which uredinia are known to 

 occur. It is suggested that the additional spore-stage, together 

 with cupulate aecia and foliicolous telia, may indicate a primitive 

 condition of this type of rust. Species occurring on the branches 

 producing fusiform swellings or gall-like outgrowths and related 

 to aecia with peridia grown out in a roestelioid fashion would be 

 later and more specialized developments. In connection with 

 such developments repeating (uredinial) stages have dropped out 

 of the life-cycle according to such a view. 



Reference has been found to only one other species of Gymno- 

 sporangium from Japan. Its standing or nomenclature appar- 

 ently has not become involved and a brief mention will be suf- 

 ficient. The first reference is to the occurrence of aecia on Pyrus 

 Miyahei by Miyabe in 1903 (Bot. Mag. Tokyo 17-: 35). He used 

 the name Roestelia solitaria but so far as I am able to interpret 

 there was not suf^cient description to establish this name. Dietel 

 in the same year proposed the name R. solenoides. Several 



^Prediction of relationships among some parasitic fungi. Science II. 31: 833. 

 1910. 



^ A Gymnosporangium with repeating spores. Phytopathology 4: 408. 1914 (ab- 

 stract). Am. Jour. Bot. 3: 40-46. 1916. 



