442 
THE PRINCIPLES OF BOTANY. 
object in this description is not to defend the rook, but to 
point out the origin of fairy-rings. 
Immediately, then, after the destruction of these discoid 
patches of herbage, the herbage all round the outer margin of 
the denuded space assumed a ring-like belt of a more robust 
grass than that of the rest of the field, and for the same 
reason that at the present moment a row of barley next to 
our farm-path is taller and stronger than the row next to it, 
the fact being that in both cases the roots have no growth on 
one side to interfere with their full development. 
In our own meadow we have at the present time some 
denuded patches of grass, caused by the leaving of separate 
lots of hay on the ground. This killed the herbage beneath, 
and now the ring of strong and taller grass, mostly of Loliurn 
perenne, is fully established. 
Now, the very vigour of growth of the rings of grass so 
established causes a secondary or outer ring, because this 
very plethora of an inner ring aids in the pauperism of the 
grasses next to them, and as starved grasses soon decay and 
die, we have in this secondary ring the very conditions 
necessary to the growth of fungi. 
Suppose fungi to have so started, their decay from the very 
chemical elements they contain necessitates a vigorous growth 
of grass on their site, and besides, the ground having rested 
for a season from growing grass, would grow it all the more 
vigorously the next, with the same results to the grass 
beyond, and thus it is that these processes continuing, a ring 
gets larger. 
That rich grass is at once formed where the Ag. gambosus 
is left, we have Mr. Way’s testimony, as well as our own 
observations in proof. He says — 
“ An experiment was made of spreading some fungi on the 
grass of the pasture where the rings occur ; the letters in the 
form of which the fungi were arranged were clearly visible a 
month afterwards.” 
We have tried the like experiments with the same effects. 
It would seem, then, that these curious circles may be 
caused by anything that may tend to destroy a disc of grass; 
but their occupancy by fungi is dependent on after circum- 
stances. If so o’ccupied, they continue year after year, and 
increase ; but if not, like many in our own meadow, they 
become broken up, and ultimately destroyed. Again, a good 
dressing of manure over a field in which they occur tends to 
the breaking up of the rings. 
That fairy-rings follow the injury to grasses by the attacks 
of insect larvae, and by the death of a disc of grass by rotting 
