54 CIRCULAR 143, U. 8S. DEPARTMENT OF AGRICULTURE 
of the plant is white, soft, and firm; as it matures it changes to yel- 
low and finally forms a purplish or olivaceous brown, dusty mass. 
All 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 commonly found 
on the ground or on old stumps or logs, and are generally clustered, 
appearing in the summer and autumn. 
LYCOPERDON PYRIFORME. PEAR-SHAPED PUFFBALL. (EDIBLE) 
(Fig. 46) 
In this species the plants are obovate, pear-shaped or subglobose, dingy 
white or brown; the cortex consists of minute, persistent warts or scales, with 
the inner coat smooth; they are sessile or with a short stemlike base and 
with white rootlike fibers; columelle are present; capillitium and spores 
FIGURE 46.—Lycoperdon pyriforme. (Edible) 
are greenish, yellow, then olivaceous. The plants are 1 to 2 inches in height 
and about 1 inch in diameter. 
This is a very common species, sometimes called the stump puffball, appear- 
ing 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 and smooth or covered with minute squamules. 
The most delicious species of puffballs belong to this genus, but as 
is the case with all fungi of this class they must be eaten while 
the interior is perfectly white. If old they are unpalatable and 
indigestible. : 
