49 

 reported by Riinpau, Vavilov says that "sterile plants of cereals as is 

 known flower ustially with open glmnes, remaining jrany days in this state, 

 and commonly are badly attacked by ergot. The sterile plants of F of the 

 hybrid of wheat and rye, for example, are severely ergotized." He concludes, 

 "evidently the sarce fact of appearance of sterile plants T^as observed in 

 the experiments of Professor Biff en at Cambridge, and, as might be supposed, 

 these sterile plants v^ere atis-cked by ergot. Vavilov* s explanation of the 

 ergotized hybrids makes the possibility of obtaining resistant strains by 

 breeding seem slight. It leads us to think that there may be an absence 

 of Mendelian characters of resistance an.d susceptibility. Still it may 

 be possible that varieties with closed gl-umes can yet be obtained by 

 this method. From a practical standpoint, such varieties serve the same 

 purpose as varieties with resistant characters. 



Clavicex)S balansioidis Ifdll. on Panicum (Echinochloa ) (ISO-- 



T3® nycelial hyphae of the fungus practically cover the T;*iole 

 spikelet or even two neighboring spiteelets. On the glumes there is formed 

 a white fluffy covering of hyphae on which are produced the conidia, Ihese 

 conidia are hyaline, oblong, and 9 to 12 microns in length. With, the 

 further development of the fungus the cavity between the glumes is filled 

 by the ngrcelial growrth vaiich later becomes the sclerotium. Then, in the 

 place of the formerly loose, white conidia-bearing mycelial growth there 

 appears in time the dark blue to black sclerotiad covering. Sometimes two 

 spikelets nay be included in one sclerotium. The lower glumes remain 

 usually outside of the sclerotium. 



The sclerotia are of various sizes. Under favorable conditions 

 they will grow above the spikelets forming sclerotia free from inclosures. 

 The sclerotia germinate in three to four months. They send out few stipes 

 with Sj^ieridia, which are yellow in color. The stipes may reach a length 



