176 BOTANY. 



abundant vegetatire filaments {mycelium) ramify through 

 the nourishing substance, and afterwards give rise to the 

 spore-fruit. The spores are produced upon slender out- 

 growths from the ends of enlarged cells (basidia), usually 

 arranged parallel to each other so as to form a spore-bearing 

 surface (hymenium), which may be external (in Toadstools) 

 or internal (in Puff-balls). Two orders may be readily 

 separated in this class, the Gasteromycetes and the Hy- 

 menomycetes. 



364. The PufF-Balls {Order Gasteromycetes). — The plants 

 of this order are saprophytes, whose spore-fruits are often 

 of large size and usually more or less globular in form. 

 The spores are always borne in the interior of more or less 

 regular cavities, and from these they escape by the drying 

 and rupture of the surrounding tissues. 



365. The vegetative filaments of Puff-balls penetrate the 

 substance of decaying wood, and the soil filled with de- 

 caying organic matter. They are colorless and jointed, 

 and usually aggregate themselves into cylindrical root-like 

 masses. After an extended vegetative period, the fila- 

 ments produce upon their root-like portions small rounded 

 bodies, the young spore-fruits, which increase rapidly in 

 size and assume the forms characteristic of the different 

 genera. 



366. No sexual organs have yet been discovered, but 

 analogy points to their probable existence upon the vege- 

 tative filaments just previous to the first appearance of the 

 spore-fruits. The spore-fruits are composed of interlaced 

 filaments loosely arranged in the interior, and an external 

 more compact limitary tissue forming a rind {peridmni). 



36T. The Puff-balls proper belong to the genus Lyco- 

 perdon, of which there are a good many species, the most 



