DIi:-r.ACK OF APPLE TRRES. 



00 



^I 



B. Grozuth on various media. 



The fungus grew well on the media tried, with the exception 

 of liquid beefbroth, which does not appear to suit the require- 

 ments of the fungus. An ascus stage failed to develop, the 

 media used and the conditions under which grown being pro- 

 bably not suited to their formation. 



Potato Plugs (PI. 23. b-e, and Fig. 2).— At 25° C. and 30° C. 

 the fungus within iive days forms a delicate pure white somewhat 

 powdery growth. After eleven days the growth, while mostly 

 flat, was of an iron-grey, and covered the whole of the potato. 

 The growth also extended into the cotton wool, which was 



coloured madder-brown (PI. 27,, b). Where fungus, glass, and 

 medium meet, a madder brown coloration is produced. At 25° C. 

 the fungus within eleven days forms small raised greyish bodies, 

 which are frequently tipped with a " dewdrop." In these bodies 

 are borne the pyncidia, either in a stroma or aggregated together 

 (PI. 23, e), though single pycnidia also occur. At 30° C. within 

 the above time there are numerous black bodies (PI. 23, c), and 

 sectioning shows that the pycnidia here are mostly simple (PI. 

 23, c) ; aggregate pycnidia as at 25° C. were not observed. 



The mycelium on potato measures 5.95 — 8.25;a across, and 



