DESCRIPTION OF PLATE XXI 
SOME TYPICAL PUFF-BALLS 
Fig. i. —Bovista plumbed ( = Lycoperdon plumbeum in Massee's British 
Fungus Flora ”): mature plant, in which the exoperidium has fallen 
away. 
Fig. 2. — Section of a young Bovista plumbed, showing the absence of 
a sterile base. 
Fig. 3. — Bovista nigrcscens (—Lycoperdon nigrescens): mature plant. 
The thin outer layer has fallen away; the thin, tough, shining skin 
well shown in the illustration is the inner layer. 
Fig. 4- — Calvatia ccelata ( — Lycoperdon ccelatum in Massee’s “British 
Fungus Flora’’) : mature plant, showing the characteristic tessellated 
appearance of the peridium, the flattened warts being surrounded by 
a meshwork of furrow’s. (All natural size, after Lloyd.) 
