454 NATURE STUDY AND LIFE 



trees in the neighborhood and report the number attacked by these 

 fungous growths. Can the children discover how the fungus gains 

 access to the wood? They may find some broken limb or some 

 place where the bark has been injured, to account for the infection. 

 With shade and garden trees all wounds should be painted over as 

 soon as made, to protect the trees from the spores of fungi. In gen- 

 eral, decaying wood, stumps, branches, or trees upon which these 

 fungi have begun to grow should be cut and burned, to prevent 

 infection of healthy trees. Any piece of rotten wood will show 

 how the fungous growth affects the tree. Seek for pieces that con- 

 tain plainly visible mycelium, white threads, permeating the wood. 

 These, as with mushrooms that grow on the ground, form the nutri- 

 tive part of the plant, absorbing certain elements from the wood 



cells, thus causing them to soften and crumble. 



At certain seasons the spore-forming portion is 



pushed out into the air. 



Spine-Bearing or Hedgehog Mushrooms, 

 Hydnacece. If a mushroom, instead of 

 gills or tubes, has spines that point 

 toward the earth, it may be called by 

 ^ther of the above names, or, botanic- 

 ally, it is a Hydnum. The class contains 

 most variant forms. Some are umbrella shaped with central 

 stems, others grow on wood and may form a mere flattened 

 layer closely attached to it, while others may develop shelf 

 or bracket forms, like many of the Polypori. Other species 

 grow in branching forms, like the coral mushrooms, but 

 are distinguished from them by the fact that the teeth or 

 spines always point earthward instead of upward. Several 

 common species are said to be edible, and no Hydnum 

 described in the books is stated to be poisonous. 



I have endeavored to give a few suggestions that may 

 form an introduction for a child to a large, interesting, and 



