378 TEXT-BOOK OF FUNGI 



the resulting peridiola eventually lie loose in the cavity of 

 the peridium, which opens at the apex. To this appear- 

 ance is due the popular name of bird's-nest fungi, the 

 open peridium resembling the nest, and its contained 

 sporangiola the eggs. In Sphaerobolus the single spor- 

 angiolum is elastically ejected to a considerable distance 

 when mature. 



Generally distributed. 



Lycoperdeae 



This family includes the puff-balls Lycoperdon^ and 

 earth stars Gcaster. 



The peridium wall is differentiated into two distinct 

 layers, which separate from each other. In Bovista the 

 outer layer of the wall breaks away in flakes. In Lyco- 

 perdon the outer wall of the peridium is differentiated 

 into spines or mealy warts that disappear as the fungus 

 reaches maturity. This outer layer is the exoperidium ; the 

 inner persistent layer enclosing the spores, the endoperi- 

 dium. In Geaster the exoperidium splits from the apex 

 into a variable number of pointed lobes which spread out 

 like rays, hence the popular name, earth-star. The endo- 

 peridium is filled at maturity with a powdery mass of 

 spores mixed with elastic capillitium threads, which escape 

 through a perforation at the apex of the peridium. In 

 the genus Myriostoma several perforations for the escape 

 of the spores are scattered over the surface of the 

 peridium, which resembles the lid of a pepper-pot. 

 Podaxon is a genus met with in South Africa, where it 

 is said to be common on deserted ant-hills. The general 

 aspect of the fungus is that of Coprinus comatus. The 



