BIOLOGIC FORMS 21 



plants, only 4 out of 40 became flecked. No pustules were developed. 



INOCULATIONS ON EINKORN 



Einkorn was inoculated with rye rust both after exposure to 

 ether for 15 minutes and without having been so exposed. The length 

 of time in ether fumes was 15 minutes. No pustules developed on 

 any of the leaves, 20 being used in- each series. 



EXPERIMENTS WITH PUCCINIA GRAMINIS TRITICI 



INOCULATIONS ON BARLEY 



It has long been a well-established fact that stem rust from wheat 

 can easily attack barley. The infection in trials made by the writer 

 was found to be normal and practically as virulent as if spores had 

 been taken directly from barley. In the one series tried especially for 

 the purpose 30 out of 30 leaves became characteristically infected. 

 There is no evidence whatever of uncongeniality between host and 

 parasite. 



INOCULATIONS ON RYE 



Inoculation under ordinary conditions 



In the control experiments 6 out of 30 leaves developed pustules 

 and 20 were strongly flecked. In fact, they were so strongly flecked 

 that flecking hardly expresses properly the appearance developed. 

 Long areas on the leaf were killed outright. In these dead areas very 

 small green islands were often found, some of which contained un- 

 ruptured pustules. All the pustules were very minute, and some had 

 ruptured the epiderm. It was another very good example of semi- 

 compatibility between host and fungus. The host leaves did. not suffer 

 very great injury; the fungus was enabled to spread to a certain ex- 

 tent but succeeded in producing only small pustules. 



Inoculation after exposure to ether for five minutes 



The results here were very striking. Fifty leaves were inoculated, 

 6 of which produced pustules, while every leaf was infected with the 

 mycelium of the rust fungus. The character of the infection was much 

 the same as was that on the check plants. The areas were perhaps 

 more extended. On some leaves there were dead areas 3 centimeters 

 long, while ordinarily they were not so long on the check plants. 



INOCULATIONS ON OATS 



Inoculations under ordinary conditions 



Direct inoculation of oats by spores from wheat has not met with 

 success on the part of either Carleton (1899, p. 54), who, however, 

 reports a doubtful case, or Freeman and Johnson (1911, p. 18), who 

 cite Derr as authority for the statement that this direct transfer can 

 be made. 



