234 E. M. CHATEE — MICROSCOPIC FtTNGI. 



but are no-n' regarded by several writers on this subject as only a 

 former stage of the same fungus. 



The pilewort is attacked by another fungus besides the JEcidium, 

 and as it is almost sure to attract the notice of those who may be 

 looking for the cluster-cups, it should not be passed without 

 remark. It is called the pilewort rust, Uromyces Ficarice, and 

 appears as a purplish brown powder bursting through the epi- 

 dermis. The spores are small, one-celled, and stalked. Besides 

 the brown rust there is also a white rust so common that it must 

 have been noticed by most of us. It attacks cruciferous plants, 

 and is seen very generally on the leaves and stalk of the shepherd's 

 purse, CapseUa Bursa-pastoris. It makes the plant look as if it 

 had been splashed over with whitewash, and as the threads of the 

 fungus gradually work their way among the tissues of the plant, 

 they cause it to become swollen and distorted, so that plants 

 attacked by this fungus present a very sickly and sorry appearance. 

 It is called the Cystopus candidus. One of the most destructive of 

 the fungi that attack lining plants is the potato mould, which is 

 the cause of the disease that does so much damage to this most 

 important vegetable. The fungus is called Peronospora infestans. 



Fig. 3. '^iR\Ae'K[ig\\i—Uncinulabicorms. 

 Lower figures — ends of appendages and spores. 



The last group of fungi that I shall attempt to notice is that of 

 the white mildews or blights. One of the most common is the 

 maple blight, Uncinula hicomis (Fig. 3), As autumn approaches it 

 is by no means uncommon to find the leaves of the maple looking 

 as if they had been dusted over with some fine Avhite powder. If 

 we pluck a leaf and examine it carefully, we can make out, even with 

 the naked eye, little black dots scattered over the wliite ground. 



