Ch. X] 



THE PUFFBALLS 



475 



Fig. 336. — Lycoperdon cyalhiforme; 

 X |. (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. 

 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). 



Fio. 337. — Geaster tenui- 

 pes; X \. (From Le Maout 

 and Decaisne.) 



