MUSHROOMS AND OTHER COMMON FUNGI. 49 



Peridium without a sterile base: 



Dehiscence apical or irregular Bovista. 



Dehiscence basal, mouth visible only after rupture of outer 



peridium t . . . Catastoma. 



Peridium (outer) splitting into stellate segments Geaster. 



LYCOPERDON. 



Species of the genus Lycoperdon are small puffballs with a some- 

 what thickened base and fibrous rooting mycelium. The peridium 

 consists of two layers. The outer, the cortex, breaks up into small, 

 soft scales, spines, warts, or granules which may soon disappear ; the 

 inner, the true peridium, is smooth, thin, and membranaceous, and 

 opens by an apical mouth. When young the interior of the plants 

 is white, soft, and firm ; as they become old it changes to yellow and 

 finally forms a purplish brown, dusty mass, composed of spores inter- 

 mingled with threadlike filaments known as the capillitium. A 

 central columella may be formed by a portion of the capillitium 

 which extends into the upper part of the plant. 



All the species of this genus are considered edible if collected while 

 the interior is firm and white ; the flavor, however, is inferior to that 

 of large puffballs. Species of Lycoperdon are common on the ground 

 or on old stumps or logs, generally clustered, and appearing in the 

 summer and autumn. . 



Lycoperdon gemmatum. (Edible.) 



Plants top shaped or with a subglobose head on a stout, cylindrical base, white, 

 becoming gray or grayish brown; outer wall, the cortex, consisting of long pointed 

 spines each surrounded by a ring of minute warts. The spines fall away, leaving 

 scars on the inner layer of the peridium. The sterile portion usually occupies more 

 than half the interior of the plant. The spore mass is greenish yellow to pale olive 

 brown. The plant is 1 to 2 inches in height and 1 to 1§ inches in diameter. 



This species appears on lawns and is common on the ground in woods. 



Lycoperdon pyriforme. (Edible.) 



Plants obovate, pear shaped or subglobose, dingy white or brown; cortex of minute, 

 persistent warts or scales, inner coat smooth; sessile or with a short stemlike base and 

 with white rootlike fibers; columella present; capillitium and spores greenish, yellow, 

 then olivaceous. The plants are 1 to 2 inches in height and about 1 inch in diameter. 

 (PI. XXXIV, fig. 1.) 



A very common species, appearing in dense clusters on rotten stumps or logs. 



calvatia. 



The genus Calvatia contains puffballs of the largest size. It differs 

 from Lycoperdon in the absence of an apical mouth and a regular 

 method of dehiscence. The plants are terrestrial, globose, or top 

 shaped, usually with a thick, cordlike, rooting mycelium. The 

 cortex is thin, smooth, or covered with minute squamules. 



The most delicious species of puffballs belong to this genus, but as 

 in all fungi of this class, they must be eaten while the interior is per- 

 fectly white. If old they are disagreeable and indigestible. 

 73431°— Bull. 175—15 4 



