284 STRUCTURE AND LIFE HISTORIES 



face in tubes (Polyporaceae, Fig. 206), another on the sur- 

 face of teeth or spines, on the under surface of the pileus 

 (Hydnaceae). The common "puff-balls" are Basidio- 

 mycetes, with the fruiting surface entirely enclosed in 

 the more or less globular fruiting body, almost the entire 

 contents of which break down into the powder or dust of 

 the ripe puff-ball (Fig. 207). Over 14,000 species of 

 Basidiomycetes have been described. 



273. Life-cycle. The life-cycle of the meadow-mush- 

 room (Agaricus campestris) may be indicated as shown on 

 page 283. 



OTHER NON-GREEN PLANTS 



In addition to the true fungi, there are two other groups 

 of non-green thallophytes which ought to be mentioned 

 here, one (the Myxomycetes) because of their scientific 

 interest; the other (bacteria) because of their economic 

 importance. 



274. Myxomycetes. The myxomycetes are on the 

 border-line between the kingdom of plants and that of 

 animals. In some of their characters they so closely re- 

 semble lower animals like the Amoeba, that they have 

 been claimed by the zoologists, under the name Mycetozoa 

 (fungus-like animals). In their method of reproduction 

 they are more like plants than like animals. 



The body of the organism is a large naked mass of 

 protoplasm, called a plasmodium, commonly found on 

 old decaying logs, in tan-bark, and similar places, where 

 moisture and organic food are abundant. The proto- 

 plast flows over the surface on which it grows, like the 

 Amoeba, taking in nourishment, at times flowing around 

 and thus injecting particles of food, assimilating, and 

 growing in size. The protoplasm may be spread out in 



