326 ECOLOGY. 



not true roots, they function as roots, or root hairs, in the ab- 

 sorption of food materials. In old cellars and on damp soil in 

 moist places we sometimes see fine examples of this vegetative 

 part of the fungi, the mycelium. But most magnificent examples 

 are to be seen in abandoned mines where timber has been taken 

 down into the tunnels far below the surface of the ground to 

 support the rock roof above the mining operations. I have 

 visited some of the coal mines at Wilkesbarre, Pa. , and here on 

 the wood props and doors, several hundred feet below the surface, 

 and in blackest darkness, in an atmosphere almost completely 

 saturated at all times, the mycelium of some of the wood-destroy- 

 ing fungi grows in a profusion and magnificence which is almost 

 beyond belief. Fig. 429 is from a flash-light photograph of a 

 beautiful example 400 feet below the surface of the ground. 

 This was growing over the surface of a wood prop or post, and 

 the picture is much reduced. On the doors in the mine one can 

 see the strands of the mycelium which radiate in fan-like figures 

 at certain places near the margin of growth, and farther back the 

 delicate tassels of mycelium which hang down in fantastic figures, 

 all in spotless white and rivalling the most beautiful fabric in the 

 exquisiteness of its construction. 



Studies of mushrooms. 



613. Form of the mushroom. — A good example for this 

 study is the common mushroom (Agaricus campestris). 



This occurs from July to November in lawns and grassy fields. 

 The plant is somewhat umbrella-shaped, as shown in fig. 430, 

 and possesses a cylindrical stem attached to the under side of the 

 convex cap or pileus. On the under side of the pileus are thin 

 radiating plates, shaped somewhat like a knife blade. These are 

 the gills, or lamellae, and toward the stem they are rounded on 

 the lower angle and are not attached to the stem. The longer 

 ones extend from near the stem to the margin of the pileus, and 

 the V-shaped spaces between them are occupied by successively 



