260 



DEVELOPMENT OF A MUSHROOM 



sequently appear in a more or less regular circle. In this way, 

 the fairy rings, which are often held in superstitious awe, come 

 about. 



The Mushroom or Toadstool. The common umbrella type of 

 mushroom consists of a stalk or stipe and a cap or pileus, on 



FIG. 1 68. 



FIG. 169. 



FIG. 1 68. The mycelium of one of the Agaricales forming white masses 

 as its spreads through wood. 



FIG. 169. Development of a mushroom: 3, early appearance of the mush- 

 room as a ball of hyphae on the strands of the mycelium. I, section of one 

 of these spherical masses of hyphae, showing the circular openings in which 

 the gills are developed. 2, a later stage with the gills formed and the velum, 

 vl, appearing asa delicate membrane. 



the underside of which are located radiating plates or gills (Fig. 

 170, A). This structure originates on a strand of the mycelium 

 as a" very small ball composed of a mass of interwoven hyphae 

 (Fig. 169, 3). Soon, however, the hyphae of this mass begin 

 to grow in a very regular manner. At first the growth results 

 in the formation of a cavity in the upper part of the ball that 

 extends completely around it (Fig. 169, i). Hyphae now grow 



