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 Amceba, 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 
