Minnesota Plant Diseases. 167 



fungi is in almost all cases of a gelatinous consistency, especial- 

 ly in the interior, and this is due to the gelatinization of the 

 outer portion of the fungus threads, which compose it. The 

 threads, therefore, appear as a very loose network in a great 

 mass of gelatine. Near the surface of the fruiting body the 

 thread walls do not gelatinize but, by the dense network there 

 produced, form a tough covering. The basidia usually cover a 

 special area as they do in the common Jews' ear fungus. In 

 the young basidium a fusion of elements similar to that in the 

 young winter spore of rusts occurs, and has also been inter- 

 preted as a breeding act. When the fruiting body is dried, it 

 usually becomes hard and horn-like and shrinks very greatly in 

 size. 



From each of the four cells of the basidium a stalk is sent 

 up to the surface of the palisade area and there pinches off a 

 single spore just as do the basidia of the rust fungi. The Jews' 



FIG. 79. Jew's-ear fungus fruiting bodies on a dead branch of balsam fir. Original. 



ear fungi have also accessory spore-forms, but not in such 

 abundance nor with such variety as they are found in the rusts. 

 The common Jews' ear fungus, which is found almost all over 

 the world, has been collected only in the northern part of our 

 state, where it occurs in great abundance on dead logs of bal- 

 sam fir, white cedar and other trees. (Figs. 78, 79.) 



Trembling fungi (Tremcllined). These fungi include forms 

 which have a great superficial resemblance to the Jews' ear 

 fungi and derive their common name from the gelatinous con- 

 sistency which allows them to tremble, as it were, at the 

 slightest agitation. They are all saprophytic, usually on de- 

 caying wood and logs. The fruiting body assumes in different 



