154: 



A TEXT-BOOK OF BOTANY 



of the markets will serve as an illustration. The myce- 

 lium of white branching threads spreads extensively through 

 the substratum of decaying organic material, and by those 



who grow mush- 

 rooms is called 

 spawn. This my- 

 celium, although 

 the least conspicu- 

 ous part of the 

 mushroom, is, of 

 course, the real 

 vegetative body. 

 Upon this under- 

 ground mycelium 

 little knob-like pro- 

 tuberances arise 

 (buttons), growing 

 larger and larger 

 (Fig. 145) until 

 they develop into 

 the umbrella - like 

 structures common- 

 ly spoken of as 

 mushrooms (Fig. 

 146). This um- 

 brella-like struc- 

 ture, however, cor- 

 responds to the 

 sporophores that 

 arise from the my- 

 celia of other groups 

 of Fungi, except 

 that it includes a large number of sporophores organized 

 into a single large body. Therefore, the real mushroom 

 body is a subterranean mycelium, upon which the struc- 



Fio. 147. Sections through the gills of a common 

 mushroom: A, gills hanging from the pileus; B, 

 single gill showing the basidium layer; C. much 

 enlarged view, showing the basidia-bearing spores. 

 After SACHS. 



