FAIRY-RING FUNGI. 



431 



toadstools (the commonest is Marasmius oreadec) that spread a 

 short distance outward every year, their mycelium destroying 

 the grass in the roots of which it grows, and so causing the brown 

 ring, on which an abundant crop of toad-stool fruits forms in 

 the fall, which by their decay enrich the soil so that it produces 

 a ranker vegetation the next season. 



An appearance which may be called false fairy-rings is occa- 

 sionally produced by PhysaruDi cinereum, one of the shine-molds, 

 on the leaves and stems of grasses. This fungus grows unnoticed 

 on decaying matter in the ground, often creeping out in a regular 

 manner from its starting point until a more or less perfect circle 

 six or seven feet in diameter is formed, when it suddenly appears 

 upon the plants it has grown under, and produces its dusty, ash- 

 colored fruit in such abundance as to attract attention from a 

 distance. From its mode of life, it does little if any harm to the 

 grass, furthei than to make a little of it unpalatable to animals. 



In closing this chapter, mention 

 should be made of small, egg-shaped 

 galls that occur on the roots of 

 clover and many other leguminoss. 

 It has been claimed that they result 

 from the attacks of a little under- 

 stood parasitic fungus {Schmzia 

 lef/wminosarum, Frank), or from 

 the presence of one of the bacteria, 

 which is apparently the case ; but 

 they have been the subject of much 

 controversy. Whatever their true 

 nature may be, they do not appear 

 to be in the least injurious to the 

 PiQ 175 plants, and may be found on nearly 



every CiOver root examined. 



