240 



PRACTICAL BOTANY 



BASIDIOMYCETES 



230. Different groups of basidiomycetes. The prominent 

 groups of basidiomycetes are : the smuts, which frequently ap- 

 pear in the heads of oats, wheat, and barley, and upon the ears 

 and stalks of corn; rusts, which are universally distributed 

 wherever wheat is grown, and which also grow upon many 



other hosts ; the toadstools, 

 mushrooms, and puffballs. 

 Next to the ascomycetes, 

 this is the largest class of 

 fungi, and is one of great 

 economic importance. 



FIG. 195. Sprays of oat plants (Avena sativa) 



The grass-like leaf character I is well known in this plant ; the plant at the left 



has developed normally, while in that at the right the grains have been destroyed 



and replaced by oat smut and the growth of the entire plant is checked. Both one 



third natural size 



