286 United States Species of Lycoperdon. 



coming flaccid ; bark adnate, subpersistent, breaking up 

 into scales or warts ; capillitium soft, dense, adnate to 

 the peridium and sterile base." 



The species of Lycoperdon are commonly known as 

 puff -halls. They belong to a group of fungi scienti- 

 fically termed Gasteromycetes because of their habit of 

 producing vast numbers of spores in the gaster or inner 

 cavity of the plant. The particular order to which they 

 belong is called Trichogasters, a name having reference 

 to the hair-like filaments which are intermingled with 

 the spores and which with them fill the interior of the 

 mature plant. These filaments form a somewhat elastic 

 mass and, being interspersed with vast numbers of minute 

 dust-like spores, if the mature plant is suddenly com- 

 pressed, they cause it to emit a little cloud of spores 

 which bears some resemblance to a pufi* of smoke. This 

 probably is the origin of the common name " pufi-balls." 

 There are two other closely related genera in this order 

 whose species emit the characteristic puff of spores. One 

 is called Bovista, the other Scleroderma. In the former 

 the outer rind or epidermis disappears as the plant ma- 

 tures and there is no distinct spongy or cellular mass of 

 sterile tissue at the base of the plant. In the latter the 

 walls of the plant are thick and firm when young and 

 they remain in nearly the same condition when mature. 

 In these respects both genera differ from the genus Lyco- 

 perdon. In it the fertile part of the plant is more or less 

 globose in shape, but there is always a mass of coarse 

 empty cells at the base which constitute a sterile part of 

 the plant, that is, it produces no spores. In those species 

 which have this part highly developed it constitutes a sort of 

 stem to the fertile part and raises it above the earth or other 

 substance on which the plant grows. When the sterile 

 base is but slightly developed the plant appears to sit di- 

 rectly on the ground or matrix and is then said to be sessile. 



