224 PEACTICAL BOTANY 



which fall from the parent plant before the spores that de- 

 velop within them are set free. A careful review of type 

 plants used in the study of green algae and phycomycetes 

 will show striking similarity in reproductive processes. 



The saprophytic and parasitic habits of living of this group 

 give them very great economic significance. Agriculture, hor- 

 ticulture, gardening, fish industries, and water supplies are 

 seriously affected by members of the group. 



217. The groups of fungi. The classification of dependent 

 plants into saprophytes, parasites, mutualists, and helotists is 



FIG. 182. Slime mold (Fuligo) growing from a decaying board 



Two masses have exuded from the crevices of the board and are rounded into 

 position for forming spores. Natural size 



based entirely upon the ways in which plants live. Fungi are 

 also classified upon the basis of their structure, and this classi- 

 fication is the one generally used in speaking of them. 1 The 

 leading groups or classes are the phycomycetes, ascomycetes, 

 lichens, and basidiomycetes. The schizomycetes (bacteria) are 

 sometimes treated in this connection, but by reason of sim- 

 ilarity of structure and methods of reproduction they and the 

 blue-green algae are now discussed together (Chapters XI 

 and XII). The last part of the name of each class (mycetes) 

 means "fungi," and the first part refers to a distinguishing 



1 The simplest acceptable classification of fungi has been adopted. Certain 

 technical groupings that are quite proper in a more advanced treatise are 

 omitted from this elementary statement. 



