34 



visible under the lower power of the microscope, so that their 

 location can be marked definitely. They can then be watched, 

 after conidiation, to see that they are the bodies which actually 

 become fertile perithecia. Figure 2 shows seven such receptive 

 bodies as they appeared at the time they were conidiated ; and 

 Figure 3, the same bodies twenty-two hours later. The second 

 picture shows that only three of the seven bodies became fer- 

 tilized. The other four grew no further because they were not 

 fertilized. 



Figure 2. Seven receptive bodies of the bakery mold, ready for fertiliza- 

 tion, at 5:30, P.M. At this time the fertilizing elements (the orange-colored 

 spores) were placed on the bodies in a drop of water. 



The story of the origin of the ascocarps usually given us in 

 text books of botany implies that there is some sort of oogonium, 

 ascogonium or female receptive body which must be fertilized 

 before the ascocarp will begin to grow. This work on Neurospora 

 shows that fertilization can be brought about after the asco- 

 gonial coils are well covered with protecting sclerotioid ele- 

 ments. That is, incipient ascocarps develop to some extent be- 

 fore fertilization. The appearance of the hair-like growths from 

 these bodies (Fig. 2) would suggest that they are all trichog- 



