2/4 



FUNGI 



under the cap are usually the most easily obtained. 

 Gather a specimen of some of these according to the 

 directions given above, and examine them as soon as 

 possible, since they decay very quickly. 



388. The Mycelium. Examine some of the white 

 fibrous substance usually called spawn, through a lens. 

 Notice that it is made up of fine white 

 threads interlacing with each other, 

 and often forming webby mats that 

 ramify to a considerable distance 

 through the substratum of rotten wood 

 or other material upon which the 

 fungus grows. These threads are 

 ^ called hypluBy and are apt to be mis- 

 taken for roots, but they are really 

 the thallus or true vegetative body 

 of the plant, the part rising above 

 ground and usually regarded as the 



525. Mycelium of a * J 



mushroom (Agaricus cam- mushroom, being only the fruit, or 



testns) with young buttons ^productive organ. The thallus of 



(fruiting organs) in differ- f . . f 



ent stages : i, 2, 3> 4, 5, sec- all fungi is called a mycehum from 



Greek word 



opment ; m, mycelium ; st, 



stipe; /, piieus; /, gill, or 389. The Button. Look on the 

 mycelium for one of the small round 

 bodies called buttons (Fig. 525). These are the beginning 

 of the fruiting body, popularly known as the mushroom, 

 and are of various sizes, some of the youngest being 

 barely visible to the naked eye. After a time they begin 

 to elongate and make their way out of the substratum. 



390. The Veil and Volva. Make a vertical section 

 through the center of one of the larger buttons after it is 

 well above ground, and sketch. Notice whether it is en- 

 tirely enveloped from root to cap in a covering membrane 

 the volva (Fig. 526, a) or whether the enveloping mem- 

 brane extends only from the upper part of the stem to the 

 margin of the cap the veil (Fig. 526, d)\ whether it has 



