THE COMMON POLYPODY IN ESSEX. 287
interesting records : seven species are now recorded from Epping Forest for
the first time, viz. :—
Lepiota clypeolaria (Bull.) Fr.
Tricholoma cinerascens (Bull.) Quel.
Collybia tesquorum Fr.
Hebeloma glutinosum (Lindgr.) Fr.
Psalliota xanthoderma Genev.
Hypholoma leucotephrum B. and Br.
Peniophora sanguinea (Fr.) Bres.
THE COMMON POLYPODY IN ESSEX:
WHY IS IT DECREASING ?
BY MILLER CHRISTY, F.L.S.
EVERYONE familiar with the flora of Essex is aware that
the true ferns (Filices) form an extremely small proportion.
It is not so much that the number of species indigenous to the
county is particularly limited ; for such is not the case. Gibson
enumerates, indeed, no fewer than twenty species as occurring.1
The point is, rather, that the number of individual plants repre-
senting those species is, in most cases, extremely small. Anyone
able to compare the fern-flora of Essex with that of Devonshire
or any other western county realizes at once the great poverty
of our county in this respect. In Essex, we have only one single
species which can be described as really abundant—the Common
Bracken (Pteris aquilina). The Polypody (Polypodium vulgare)
is, however, quite common, and the little Adder's-Tongue
(Ophioglossum vulgatum) is fairly so. Devonshire, on the other
hand, has at least a dozen species, all of which are more or less
abundant.
That the fern-flora of Essex must always have been very
meagre, not only comparatively, but actually, is certain ; for
Essex, as the driest county in England, lacks that humidity of
climate, due to heavy rainfall, which is so necessary for luxuriant
fern-growth. Our mean average rainfall is about 23 inches
annually : that of Devonshire, about 41 inches, or nearly twice
as much. There, the climate is so moist that fern-spores propa-
gate readily every year ; whereas, in Essex (as Mr. Shenstone
1 Flora of Essex, pp. 394-404 (1862).