32 



Minnesota Plant Diseases. 



the fly on panes of window glass in the autumn. A very com- 

 mon dung-inhabiting mold has also an explosive apparatus. 



Fic. 14.— Various explosive apparatuses for distributing spores. 1. Sac fungus — spores are 

 blown out of the sac when the lid is also blown out. 2. A black mold — the whole top 

 of the spore case with spores is blown off; on right unopened case — on left, case is 

 being blown off. 3. Sphere-throwing puff-ball — showing a longitudinal section with the 

 spore mass ready to be thrown out. 4. The spore mass is ejected by the inversion of 

 the fruiting-body coats. 5. The fly cholera fungus (an insect mold). To the right a 

 spore has been snapped off with a small surrounding mass of sticky fluid which serves 

 to fasten the spore to another insect. 1, after Engler and Prantl; 2, 3, 4 and 5, after 

 Zopf. 



This fungus forms numerous spores in a case on the end of a 

 fungus thread. The thread just beneath is much swollen and 

 under pressure, until at the ripening of the spores the whole 



