176 Borany. 
abundant vegetative 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 (dasidia), 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 (peridium). 
367. The Puff-balls proper belong to the genus Lyco- 
perdon, of which there are a good many species, the most 
