242 



MYCOLOGY 



to October. It is an extremely variable species, Lycoperdon gemma- 

 turn, an olive-spored species, has a turbinate shape, its outer peridium 

 being marked with long, thick, erect spines, or warts of irregular shape 

 with intervening smaller ones, whitish, or gray in color. The larger 

 spines fall away first imparting to the surface of the peridium a reticu- 

 late appearance. It often grows cespitosely on the ground, or rotten 

 tree trunks in woodlands. Lycoperdon pyriforme is another common 

 species found in woods and clearings on the ground, or on decaying 

 wood. It is edible, tender and of second-class flavor when young. 



Fig. 96. — Fruit-body of Calvatia cyalhiformis. {Photo, by IF. H. Wahnsley.) 



The largest puff-balls are included in the genus Calvatia (Fig. 96), 

 which differs from Lycoperdon in the absence of an apical mouth and 

 a regular dehiscence. The fruit bodies are globose, or top-shaped, aris- 

 ing on the surface of the ground from subterranean, cord-like hyphae. 

 Calvatia cyathiformis (Fig. 96) which is edible, if eaten when white in- 

 side, grows in open grassy fields and lawns and reaches a diameter of 

 three to six inches. Calvatia gigantea, the giant puff-ball, grows in 

 pastures and meadows. Usually the fruit bodies are ten to twenty 

 inches in diameter and even larger. The genus Bovista has a fragile 



