292 FHE ESSEX NATURALIST. 
there. must be some special cause, of a general nature, to account 
for its very marked decrease throughout Essex; but it is not 
easy to perceive just what that cause may be. 
In the case of the Roothings, there can be little doubt that 
the clearing away of old tree-stumps and the cutting down of 
hedges (now customary to a very much greater extent than 
formerly, as a result of modern agricultural methods) is to a 
large extent accountable for the decrease.’ Yet it 1s impossible 
to suppose that this can have been the sole cause ; and; in 
any case, this cause cannot have been accountable for the 
decrease of the Polypody in Epping Forest. A steady decrease 
in rainfall during the last fifty years or so might easily account 
for the general decrease of the fern throughout the whole 
county ; but, so far as I am aware, no such decrease of rainfall 
has been recorded.® 
Why, then, has the Polypody decreased so ra 
in Essex ? I confess myself at a loss to explain it. | 
8 Mr. Chancellor’s observations from pee to 1903 (Essex NAT., xii. (1903), pp. 248-250) 
show no such decrease. ea ee 
END: OF \VObe ae 
