1920] BISB Y—UROM YCES 207 



upon hosts belonging to the various sections of the genus Euphorbia. 

 That these species are related is evidenced by the fact that many 

 had passed under one name; furthermore, many similarities are to 

 be noted from Tranzschel's descriptions. For example, all but 

 one species are listed as having verrucose or striolate teliospore 

 walls. A table showing characters in a manner similar to those 

 tabulated under U. heterodermus would be illuminating as indicating 

 relationships between U. Tranzschelii and other species of rust upon 

 related hosts. The writer considered it sufficient, however, to 

 call attention to Tranzschel's work as indicating relationships. 

 Certain heteroecious species with aecia upon Euphorbia likewise 

 show resemblances to U. Tranzschelii. 



Both Ellis and Everhart's Fungi Columbiani 1069 and North 



Garrett 



Magn 



American 



The range of U. Tranzschelii begins at about the western 



proeminens 



and 



Range conditions 



comparable with those of U. abbreviatus are thus shown, and neither 

 of these short cycle forms necessarily occurs at high altitudes. 



Tranzschel (loc. cit., p. 20) considered the rust upon Euphorbia 

 Palmeri to be different, apparently another species. The specimen 

 studied by the writer is not considered different from other 

 specimens of U. Tranzschelii. 



Dietel {loc. cit.) commented upon Ellis and Everhart's 

 North American Fungi 22 30, especially concerning the relationship 

 of an Aecidium upon the same host distributed as no. 2215 of the 

 same exsiccati. It is true that Aecidium Tithymali Arth. occurs 

 upon the same hosts, sometimes upon the same leaves, as Uromyces 

 Tranzschelii. The situation in regard to this Aecidium Tithymali 

 is uncertain. Germination tests show that it is a true Aecidium 

 and not an Endophyllum. Its alternate host, however, has not 

 been found. Arthur {loc. cit) has discussed this Aecidium and 

 its possible relation to U. Tranzschelii. 



6. Uromyces nevadensis Hark. Bull. Calif. Acad. Sci. 1 :36. 

 1884. — Caeomurus nevadensis Kuntze, Rev. Gen. 3 3 :45°- 1898. 



