STUDIES OF SPORE-PLANTS 265 



posed of closely packed and interwoven threads or hyphae, 

 which have the same structure as the hyphae below ground. 

 The part above ground is, then, a sort of branch of the sub- 

 terranean mycelium. 



Reproduction. A new mycelium is produced by germina- 

 tion of a spore which falls in a favorable place. The stalk 

 and cap raise the spore-producing hyphae above ground so 

 that the spores may be more widely disseminated. 



" Fairy-rings." A mycelium once started in the ground 

 may continue to grow and produce new mushrooms for 

 some time. Frequently mushrooms are seen in pastures 

 arranged in circles. These were once popularly supposed 

 to have been caused during the night by fairies in their 

 dances, and were called fairy-rings, or fairy-circles. This in- 

 teresting explanation was especially applicable to rings formed 

 by certain minute relatives of the mushroom which give the 

 soil the appearance of having been sprinkled with ashes. 

 But science has in many ways given us rational explanations 

 of many puzzling things in nature, and we no longer need 

 to assume the existence of fairies and other mythical beings. 

 Scientific study of the " fairy-circles " long ago showed that 

 they are caused by the regular growth of a mycelium from a 

 center, and as the older and central portions die, the mush- 

 rooms will appear in continually widening circles. 



Cultivated mushrooms are grown from " spawn " which 

 comes from seed dealers in the form of dry bricks composed 

 of partially decayed vegetable matter. The spawn is really 

 nothing but mycelium, either taken from old mushroom 

 beds, or started by scattering spores over materials out of 

 which the bricks are to be made as soon as the spores have 

 germinated and formed an extensive mycelium. It is simply 

 necessary to break such bricks into pieces and plant them in 

 a bed of suitable soil with abundance of decaying organic 

 matter. Concerning the cultivation of mushrooms see 

 Farmers' Bulletin No. 204 (free). 



