26o 



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. i68. Fig. 169. 



Fig. 168. 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 as a 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 



