48 MAINE AGRICULTURAL EXPERIMENT STATION. I9IO. 



are 11-14 microns in diameter and are borne on branches which 

 vary considerably in length. Some asci are foimd which are 

 less than 11 microns in diameter and some are found which are 

 not spherical being somewhat pear shaped. In some cases also 

 rather abnormal development of the spore sacs takes place as 

 shown in Fig. 70, but by far the most common method of pro- 

 duction of asci is for a number of single asci to develop on short 

 branches from a hypha, as shown in Figures 60, 61, 62 and 65. 

 In order. to determine the extent of variation in growth of 

 the fungus and the effect upon its reproduction, it has been 

 grown upon a rather large number of culture media. 



Cultural Characters. 



When the conidia are placed in a hanging drop of prune de- 

 coction, potato broth, or beef extract broth plus 2 per cent dex- 

 trose, at room temperature, they germinate readily. The con- 

 idia become considerably swollen and within 4-5 hours a num- 

 ber of them will begin to put out germ tubes. As a rule the 

 conidium puts out only one germ tube but in some cases two 

 are produced from opposite sides of the spore. In some cases, 

 even in the hanging drop, the germ tube may grow out to form 

 a branched mycelium on which short conidiophores bearing the 

 conidia are borne as shown in Fig. 66. In other cases, the 

 germ tube may grow out and begin to bud off conidia from the 

 end within 16-18 hours. Some conidia are formed in very ir- 

 regular ways as shown in Fig. 67. The conidia did not germi- 

 nate in hanging drops of neutral beef extract broth. 



The ascospores germinate, in some cases at least, while still 

 in the ascus. Material from a culture 3 weeks old growing on 

 bean agar and in which there were a large number of asci which 

 contained spores was thoroughly washed to remove conidia and 

 then teased apart and enough material to contain several asci 

 in each case was placed in each of 5 hanging drops of prune 

 decotion. After 16 hours, examination showed that in a num- 

 ber of asci one or more of the spores had germinated. ' Here, as 

 in the case of germinating conidia, some of the germ tubes grow 

 to form a branched mycelium and in some other cases conidia 

 are formed on the end of the germ tube within 18 to 24 hours 

 after the spores are sown as shown in Figure 69. 



