THE MUSHROOM 109 



Hymenomycetes and the Gasteromycetes. The Mush- 

 room is a good type of the former, and the Puffball of 

 the latter. 



Agaricus campestris, the Common Mushroom, as 

 ordinarily gathered, is merely the fructification of a 

 Fungus, whose vegetative part, the mycelium, lives 

 saprophytically in richly manured soil. The mycelium 

 consists of long, branched, many-celled hyphae, which 

 ramify through the material in which they subsist. 

 The Mushroom " spawn," sold in the form of bricks, is 

 really a compressed mass of manure and soil containing 

 mycelia. The real Mushroom plant, then, grows in 

 darkness under the surface of the soil. It is probable 

 that from the time of the germination of a spore the 

 mycelium grows and ramifies vegetatively for about 

 seven months before it takes the sudden notion to pro- 

 duce fructifications with almost magic speed. 



Fig. 36 illustrates the development of a Mushroom. 

 A represents a mycelium composed of branched hyphse, 

 bearing fructifications in early stages of development. 

 B is a young fructification, seen in section, with attached 

 pieces of the mycelium (m). C and D are advancing 

 stages in which the gills (I) are developing. In E, a 

 later stage, we see some differentiation; we note the 

 thick stalk, more properly called the " stipe " (st), the 

 velum (v), and the gills, or lamellae (/). F shows a nearly 

 ripe specimen, in which we note the pileus, or cap (h), 

 born upon the stipe, and the velum, or veil (v), which 

 in ripe specimens is broken, leaving a ring upon the stipe. 

 The velum protects the under-side of the pileus with its 

 gills during growth; it is shattered later, in order that 

 the gills may be exposed and the spores scattered. 



