THE PUFF-BALLS 131 



hollow and destroyed the contents of the acorns, leaving only 

 the hard shells looking exactly like fossil eggs in the matrix. 



The higher fungi include many other interesting plants. The 

 Puff-Balis have a spherical or pear-shaped fruit, which opens by 

 a small hole at the top. The whole fruit, when ripe, consists 

 of a thin skin containing a powdery mass of spores, and these 

 are thrown out in " puffs " as the fruit dries and contracts. 



BIBLIOGRAPHY. Guide to Sowerby's Models of British Fungi, published at 

 the Natural History Museum, South Kensington, 4<i. 



