248 



PEACTICAL BOTANY 



236. Toadstools and mushrooms : structure and reproduction. 



The mycelium often becomes very extensive, and may form 

 moldy or cobweb-like threads within the rich earth, decaying 

 wood, or other nourishing substratum. When it grows, the 

 mycelium helps to bring about the decay of the material which 

 nourishes it, and therefore may be very destructive. The 



Fig. 202. A large toadstool 

 Note the stalk, the ring, the crown, and the gills. One third natural size 



mushroom spawn, which is sometimes especially prepared and 

 sold ill bricks to tliose who wish to grow muslirooms, is sim- 

 ply a mass of mycelium. At times there form aggregations 

 of the mycelium, which are whitish, bud-like growths called 

 " buttons," and which are the beginnings of the structures 

 known as toadstools or mushrooms. They grow and push then- 

 way to the surface. As the "button" elongates, its top begms 

 to expand into the umbrella-like form, and finally opens out 

 as the crown or pileus, with its center attached to the upper 



