PUFFBALLS AND RELATED FORMS (GASTEROMYCETES) 391 



A very interesting Puffball is the Earthstar (Geaster) shown in 

 Figure 347. In this form the outer layer of the peridium splits 

 into regular segments and these segments are hygroscopic. 

 When the segments are wet they bend back and downward and 

 in this way the outer layer 

 of the peridium spreads out 

 like a star. The inner layer 

 of the peridium opens by an 

 apical pore and allows the 

 spores to escape as in other 

 Puffballs. 



The Bird's Nest Fungi 

 (Fig. 348), which are close 

 relatives of the Puffballs, 

 show another interesting fea- 



ture. They are small, usu- 

 ally less than a centimeter 

 in height and width. They 

 develop on twigs and sticks 

 as well as on organic matter 

 that is quite well decayed. One often finds them growing on the 

 benches in greenhouses. The chambers of the gleba become 



FIG. 346. Puffballs, Lycoperdons. 

 Three have opened at the top, thus 

 allowing the spores produced in the in- 

 terior to escape. X |. 



FIG. 347. An Earthstar, Geaster. About natural size. 



enclosed in walls and separate. After the peridium opens, the 

 sporophore is cup-shaped and, with the egg-like chambers of the 

 gleba exposed, resembles a bird's nest full of eggs. 



The Stink Horn (Fig. 849), noted for its intolerable odor, is 

 another Fungus of this order. Its mycelium feeds on decaying 



