214 
Journal of Agricultural Research 
Vol. XI, No. s 
It has been difficult to determine the number of distinct forms occurring 
as fairy rings in eastern Colorado. The first form to appear in the spring 
is Agaricus tabular is, ranging morphologically from typical A. iabularis 
to the smooth expanded type similar to A . arvensis . Later in the season, 
if moisture conditions are favorable, a series of smaller forms {A. campes- 
tris) appear which show almost as wide a range in morphological charac¬ 
ters as does A . iabularis , but which are entirely distinct from the latter 
in time of appearance and in the character of the mycelium in the fairy 
ring. The mycelium is not dense in the soil. The whole plant is less 
vigorous, the fruiting 
bodies are smaller and of 
a more delicate texture. 
But in this group the 
fruiting bodies often be¬ 
come decidedly rough 
on top and present wide 
variability in the ap¬ 
pearance either of the 
fresh or the dried forms. 
The appearance of the 
fairy rings produced by 
the A. iabularis group 
is entirely distinct from 
rings of the A . campes - 
iris group. 
The effect of the dry 
climate on Calvatia 
cyathiformis is not as 
marked as on Agaricus 
iabularis . The perid- 
ium, which is usually 
dried rapidly, has a 
rough tabular appear¬ 
SHC&T’ 
a&tss 
300 
CO/?// /73AO 
a . 
-> 
r 
* 
0 CL 
0 0 0 0 0 
0 0 
0 
0 
0 
0 
0 
'°o° 
0° 
00 
•- £MAf£T£-/? 47’A?£7E?S - > 
Fig. io.—This Agaricus iabularis ring was partly within a cornfield 
and partly within the native short-grass sod. At one side the 
ring had been interrupted by the presence of a pond. The mush¬ 
rooms in the cornfield showed a taller stipe, a more expanded 
pileus, and a smooth top, while those in the short grass showed a 
short stipe and a compact pileus with a roughened top characteris¬ 
tic of Agaricus iabularis. 
ance. As soon as dry, these scales fall off, exposing the spore area 
underneath (Pi. 27, A). The same is true of Calvatia fragilis. Calvatia 
polygonia produces a heavy, thick, scaly peridium (PI. 29, A, B), which 
responds especially to the dry conditions of the atmosphere. If the 
young puffballs are injured, they break open, forming abnormal fruiting 
bodies, such as shown in Plate 29, C. These fruiting bodies dry up be¬ 
fore mature spores can be produced. 
AGE AND RATE OF ADVANCE 
Very little data are available on the rate of advance of fairy rings. 
Hutton (1790) observed this advance during a period of eight or nine 
years, but gave no data as to rate. Wollaston (1807) measured the 
