CH. X] 



THE PUFFBALLS 



475 



FIG. 336. Lycoperdon cyalhiforme; 

 X i. (After Peck.) 



imating towards globular form, remain closed until the spores 



are all ripe. They include some 700 species, and are of slight 



economic importance. 



The best known and most typical members of the order are 



the Puffballs (Fig. 336; also 62). The subterranean sapro- 



phytic mycelium produces 



at the surface round masses 



of hyphae, which gradually 



differentiate into a thin 



brown parchment-like wall 



(PERIDIUM), and an interior, 



chambered, soft mass of 



intermingled hyphse and ba- 



sidia (GLEBA), producing 



copious basidiospores. In 



ripening, the spores become 



dry, loose, and dark colored, 



and gradually escape through apical openings, from which 



they may be made to puff by sudden pressure. Some of the 



kinds break loose from the mycelium, and are rolled by the wind 



over the ground, thus scattering the spores. One kind attains 



a diameter of a foot and a half, and most of them are edible. 



Closely related are the remarkable 

 Earthstars (Geaster species), which 

 are practically Puffballs in which 

 the wall is double. The outer layer 

 splits into regular segments (Fig. 

 337), free above, but attached below. 

 FIG. 337.- Geaster tenui- These segments are hygroscopic, and 

 curl backward and downward in wet 

 weather, often so strongly as to lift 



and break the structure from the mycelium; and then 



the wind rolls it over the ground, scattering its spores. 



Some of these Earthstars contain a capillitium, in form 



and function strikingly like that of some Myxomycetes 



(page 413-4). 



pes; X I- (From Le Maout 

 and Decaisne.) 



