THE BASIDIUM FUNGI (BASIDIOMYCETES) 247 



fruit of the apple tree, or other members of the apple family. 

 The apple tree is thus infected, and during the summer the 

 cups bearing secidiospores are formed. Some of the secidio- 

 spores may fall upon the cedar and reinfect that host. In 

 late summer and autumn "cedar apples" are again produced. 1 



235. Toadstools and mush- 

 rooms. These fungi are char- 

 acterized in general by the fact 

 that the mycelium lives entirely 

 within the material which fur- 

 nishes its nourishment, and oc- 

 casionally sends up into the air 

 the spore-bearing structure that 

 is called the toadstool or mush- 

 room. Scientifically there is no 

 accepted distinction between 

 toadstools and mushrooms. 



Those forms that are known 

 to be good to eat are popularly 

 spoken of as mushrooms, while 

 those that are not edible, or 

 that are poisonous, are called 

 toadstools. Even this distinc- 

 tion, which is wholly popular 

 and was made solely upon the 

 basis of real or supposed edibil- 

 ity, is not easily applied, since little is known regarding the 

 edibility of many species. Furthermore, in a given genus some 

 species may be excellent for food, and others poisonous. Cer- 

 tain edible species are easily learned and are not readily con- 

 fused with those which are poisonous. 2 There are over one 

 thousand edible fungi which grow in the United States. 



1 "The Cedar-Apple Fungi and Apple Rust in Iowa," Bulletin 84, Iowa 

 Agr. Exp. Sta., 1905. 



2 The United States Department of Agriculture publishes several bulle- 

 tins upon poisonous and edible fungi. 



FIG. 201. A ff cedar apple "(Gymno- 

 sporangium) in its spring condition 



The extrusions are made up of hyphae 

 and teleutospores. Three eighths nat- 

 ural size 



