302 OBSERVATIONS ON VEGETABLES. 
discovered by the dogs as those that lie deeper. Half a crown a 
pound was the price which he asked for this commodity. 
Truffles never abound in wet winters and springs. They are 
in season in different situations, at least nine months in the year. 
TREMELLA NOSTOC. 
Though the weather may have been ever so dry and burning, 
yet, after two or three wet days, this jelly-like substance abounds 
on the walks.* 
FAIRY RINGS. 
The cause, occasion, call it what you will, of fairy-rings, subsists 
in the turf, and is conveyable with it ; for the turf of my garden- 
walks, brought from the down above, abounds with those appear- 
ances, which vary their shape, and shift situation continually, 
discovering themselves now in circles, now in segments, and 
sometimes in irregular patches and spots. Wherever they obtain, 
puff-balls abound ; the seeds of which were doubtless brought 
in the turf.f 
* This is commonly called ** fallen stars" in many places, a most unaccountable name, which 
is also sometimes applied to the spawn of toads. It is a modification of the fungus tribe, which 
dries up till it becomes imperceptible in dry weather. — Ed. 
t The cause of " fairy rings" is still a subject of discussion, and I suspect the truth is that 
there are different kinds of them. Some i have no doubt are occasioned by minute centrifugal 
f'ungj. — xuo. 
