FLOWERLESS PLANTS 445 



the base of the stem, selecting specimens with a large ball 

 of earth. They should find an irregular mass of white 

 threads, some of them running into the bottom of the stem. 

 They may also find among these threads "buttons" of 

 various sizes. These are young mushrooms that will grow 

 larger and finally push their way up into the air, for what 

 purpose we shall see in a moment. Have the class com- 

 pare their specimens and try to find a series from the 

 smallest "button" to a full-grown mushroom. Do any in 

 the class know what relation the white threads bear to the 

 mushrooms? While not conspicuous these are really the 

 main part of the plant. They are called the "mycelium" of 

 the mushroom. This mycelium may grow for months or 

 even years, sending thread after thread in every direction 

 through the soil or through the wood of a tree, absorbing 

 food and increasing in size. It is thus the vegetative or 

 nutritive part of the plant. We shall find something 

 similar when we study the moulds. When the proper con- 

 ditions arrive, generally after heavy rains (for mushrooms 

 are almost all water), the "buttons" enlarge and push up 

 through the surface, often in a night. Fig. 179 will serve 

 to explain the conspicuous parts of a mushroom stem, 

 cap or pileus, gills or spore-bearing structures. Emphasize 

 the fact that the mushrooms that we ordinarily see are only 

 the spore-bearing, or reproductive, part of the plant. They 

 are pushed up into the air by the mass of the mycelium, in 

 order that the spores may be carried in every direction by 

 the winds. 



Let us next ask the children to study the sporing of 

 their mushrooms. From any large specimen the spores 

 are probably being shed, from between the gills or from 



