PROTOBASIDIOM YCETES 4 1 5 



The maize fungus has recently been connected with an ^Ecidium 

 m Oxalidis Thiim.) on Oxalis, so that its heteroecism is 

 established. This aecidial stage has seldom been found, and there 

 is reason to believe that the uredo stage may commonly serve to 

 carry the fungus over winter. 



XV. TIMOTHY RUST 

 Puccinia Phlei-pratensis Eriks. & Henn. 



ERIKSSON, J., u. HENNING, E. Die Hauptresultate einer neuen Untersuchung 

 iiber die Getreideroste. Zeitsch. f. Pflanzenkr. 4: 140-142. 1894. 



ERIKSSON, J. Ueber die Specialisirung des Parasitismus bei den Getreiderost- 

 pilzen. Ber. d. deut. Bot. Ges. 12: 292-331 (cf. 309-316). 1894. 



KLEBAHN, H. Die wirtswechselden Rostpilze, /. c., pp. 235-236. 



Timothy rust is common in Europe, occasionally damaging to 

 a noticeable extent the cultivated timothy (Phleum pratense). It 

 also occurs upon some other cultivated and native grasses. The 

 fungus is unquestionably closely related to Puccinia graminis, if 

 not a form of this species. It is reported ineffective in producing 

 the cluster cup of the barberry. During the past' few years the 

 timothy rust has been found in a considerable portion of the east- 

 ern United States, although previously it had not been noticed, 

 at least to any practical extent. It is not yet positive that the rust 

 which occurs in America is the same as the European species. It 

 is conceivable that the cultivated timothy has gradually become sus- 

 ceptible to another form of Puccinia graminis, but this remains to 

 be determined by careful experimental work. The European rust 

 has not been connected with an aecidial stage, and it has been 

 shown that the uredospores are apparently capable of wintering 

 over, and therefore the disease may be readily reproduced from 

 season to season without an aecidial stage. If the appearance in 

 America means a sudden introduction and rapid spread of the 

 European rust, much damage may be expected from it. On the 

 other hand, it may have been parasitic upon timothy for some 

 time without having attracted attention. Experiments made by 

 Eriksson in the open indicate that the rusts on timothy and 

 meadow fescue are readily transferred from one of these hosts 

 to the other, and with much less success to several other grasses 

 employed in the experiments. 



