Parasitic Fungi of Illinois. 



391 



Figure 2. Cicinobolus Cessatii, DBy. : a 

 the mycelium of Erysiphe galeopsidis, DC, 

 within which is to be seen the parasitic 

 mycelium b of Ckinoblus; c, c, c different 

 stages of the so-called pycnidium in which 

 the spores of the parasite are developed. 

 Magnified 300 times. (After De Bary.) 



FlO. 2. 



This frequently develops in one of the cells of a conidio- 

 phore, in which case the shriveled upper portion remains as a 

 kind of appendage. In other cases it is developed directly from 

 the mycelium. Occasionally, on rupturing a perithecium, it will 

 be found to contain minute bodies like Cicinobolus spores, 

 instead of asci. This is considered a fourth kind of reproduc- 

 tive body by Berkeley (Introduction to Crypt. Bot. p. 78). It 

 is more likely a case of the Cicinobolus developing its fruit 

 within the growing perithecium. 



This parasite has been mostly investigated in connection 

 with the grape mildew (Erysiphe Tuckeri). Some writers 

 suppose it to be of considerable use in holding this disease in 

 check (Thumen, Pilze des Weinstocks, p. 178). It occurs on 

 several of our specimens of Erysiphe cichoracearum, DC, w T here 

 its delicate mycelium can be seen by the aid of a good objective 

 and careful manipulation. 



Various Macrosporium- and Helminthosporium- like bodies 

 are frequently associated with Erysiphe mycelium, but their 

 organic connection with it is doubtful. Minute yellow r spher- 

 ical echinulate bodies are also often seen clinging to it, but they 

 are foreign substances, — probably pollen grains. 



The abundant mycelium of these plants is so conspicuous 

 that it early attracted the attention of investigators. The 



