rvoL. 2 



638 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



appear superfluous, for their galls pass through the concavity 

 stage and the morphological characters of the fungi concerned 

 differ in no respect from those of E, Vaccinii, 



Exohasidium Cassandrae was based on a leaf concavity of 

 Cassandra calyculata. The new host was the sole basis for 

 this new name and its author closed his description with the 

 comment, ^ * perhaps this is only a form of E. Vaccinii. ' ' Since 

 we now regard E, Vaccinii as able to infect many species of 

 the Ericaceae, the host alone in this case (with the morpho- 

 logical characters of the fungus agreeing with those of E, 

 Vaccinii) does not afford sufficient justification for regarding 

 E. Cassandrae as distinct from E, Vaccinii, 



Exohasidium Arctostaphyli was founded on a leaf spot on 

 Arctostaphylos pungens. As in the case of Exohasidium Cas- 

 sandrae, there is no evidence whatever that the fungus con- 

 cerned is not E, Vaccinii, the characters of the fungus and its 

 work being quite those of the latter species. 



The usual errors in connection with the preceding series of 

 synonyms which are grouped together in the second division 

 of my table are due, it seems to me, to attaching to a strange 

 gall form a host product the same weight which one would 

 give to a toadstool, and to ignoring the true fructifications of 

 the Exohasidium concerned. In the taxonomy of the Hy- 

 menomycetes, species are based upon differences in morpho- 

 logical characters. It is so remarkable an innovation in our 

 taxonomic usage in this group of plants to propose a new 

 species which has precisely the same morphological characters 

 as a well-known and established one that it makes it incum- 

 bent upon, and an unusual opportunity for, an author so 

 establishing a species to show conclusively the truth of the 

 paradox that actually good and distinct species of Hymenomy- 

 cetes have the same morphological characters. In all the 

 <3ases which have been considered, no evidence tending toward 

 such proof has been offered. In the above, I but express the 

 views of many of the best mycologists, who have consistently 

 regarded the above-mentioned Exohasidium names as 

 synonyms of E. Vaccinii. 



