39 



In one case, C. ruprpurea biologic race on BrachypodiTan 

 silvaticum, Tbose sclerotia germinate long before the flowering of 

 the host, B. silvaticum . the fungus must pass first to Milium effusum , 

 ViSiich is in blossom at the time the ascospores are discharged. On this 

 host it produces the sphacelia stage and then these conidia are carried 

 over to B. silvaticum v/here they cause new infection. 



Overwinter jnA' of the causal organism 



All Claviceps species over\7inter in the forai of sclerotia, the 

 function of which is to carry the fungus through unfavorable conditions. 

 Even though conidia, if kept dry and in the dark, preserve their 

 germinating power for over ten months, it is very unlikely that in nature 

 such conidia would survive for any length of time. There is, however, 

 no experimental evidence bearing on ttiis point. 



...A method of developing the Claviceps stage 



It is often desirable to be able, to produce the ascigerous 



stage of Claviceps from ergot sclerotia for class use or experimental 



purposes. Different workers have accomplished this in various \vays, 



with 

 but \iftietzel and Reddick (294) describe a method'Nshich they were very 



successful. The following is a description of it. jJC-bout the middle of 

 August they gather fresh sclerotia from the heads of rye or other in- 

 fected plants. These are then enclosed in ordinary screen wire and 

 put on the ground under a tree. The sclerotia are not d-istmibed until 

 about April 6 the following jT-ear xvhen they are taken to the laboratory 

 and placed in moist sand in a covered stender dish and kept at room 

 temperature. About tv/o weeks later the first signs of germination 

 begin to appear. By tlae middle of May a majority of the stromata will 

 be ■^v^iopfd jand a great imny of them will contain mature ascospores. 

 The time of appearance of stroiiiata n.ay, hov^ver, vary slightly for 

 ^ffexent seSierotia^ 



