392 



THALLOPHYTES 



organic matter in the ground. The sporophore is at first globose, 

 but the gleba soon breaks out of the peridium and is elevated to 

 some distance above ground by an elongating stalk. The spore 



masses are slimy and have the odor of 

 carrion. Certain insects which dissemi- 

 nate the spores are attracted by the 

 odor. 



Smuts (Ustilaginales). The Smuts 

 are parasitic Basidiomycetes. In some 

 Smuts, the mycelium, although evident 



FIG. 348. -A Bird's nly * local areas traverses widely 

 Nest Fungus, Nidularia. through the host, while in others only 

 About natural size. local areas of the host are attacked. 



No sporophores, such as characterize 



the Toadstools and Puffballs, occur in the Smuts. There are 

 more than 2000 species of Smuts. They attack chiefly plants 

 of the Grass family and espe- 

 cially the cereals, the grains of 

 which they commonly displace 

 with powdery black masses of 

 spores. The financial loss due 

 to Oat Smut alone has been 

 estimated to be $10,000,000 

 annually in the United States. 

 In addition to the loss due to 

 the destruction of the cereal 

 crops and the lowering of their 

 market price, there is consider- 

 able loss due to Smut explosions 

 in thrashing machines. During 

 the summer of 1914, 300 thrash- 

 ing machines were blown up or 

 burned in the Pacific Northwest 

 by Smut explosions. Smut dust 

 is highly combustible when dry, 

 and is probably ignited by static peridium. 

 electricity in the cylinder of the 



thrashing machine. The Smuts are particularly destructive 

 to Oats, Wheat, Rye, and Barley. Corn Smut is exceedingly 

 common but less destructive. 



FIG. 349. Stink Horn Fungus, 

 Phallus impudicus. At the right, 

 vertical section of the Fungus in 

 early stage of development, showing 

 the gleba enclosed by the peridium. 

 At the left, mature stage, showing 

 the gleba elevated much above the 

 X i 



