A MS. ESSEX FLORULA.
305
hood of Bentley and Tattingstone, the clay is covered by the
beds of the Crag formation, abounding in organic remains.
"In connection with the geology of the country, the Alder
Cars, which here form a peculiar feature, deserve mention. In
most districts the swampy declivities of hills where springs
abound are occupied by bog; but the Cars, which here hold this
position, are deficient in the two characteristics of bog, iron and
the moss Sphagnum. The want of the former I take to be the
cause of the absence of the latter ; but this I cannot positively
assert.
"The number of species included in the list is 592. Of these
about 35 are due to the presence of salt water ; but, even when
these are deducted, the number (557) considerably exceeds that
of the species which fell under my notice in an equal space of
time at East Grinstead, in Sussex (520), and at Hertford (510).
The neighbourhood of Dedham may therefore be fairly considered
as a productive botanical country, notwithstanding the absence
of many species from the total want of chalk and bog, and the
great scarcity of heath. But nevertheless, I am far from sup-
posing that I have thoroughly examined the country; and I
have no doubt that a careful observer will be able to add many
new species, as well as many stations of the rarer ones, which
have either been overlooked or removed from my notice owing
to my absence from Dedham for nearly two months at the height
of the season. I have since had experience at Hertford, where a
second year has added upwards of 100 species to those observed
in the first.
"With respect to the words 'common,' 'frequent,' &c.,
used to denote the comparative frequency of the species, I must
beg the reader's indulgence for inaccuracies which (owing to
my short residence in the vicinity and my absence before men-
tioned) could hardly be avoided. Thus I find myself totally un-
able to say whether Chrysanthemum leucanthemum is a rare
or common plant ; it flowered during my absence, and I saw it
in two or three places only after my return : and the same is
the case with several others. Several species are in all probability
confined to one side of the Stour ; but I am not able to point
out these farther than is done in the Catalogue. Few of the
plants enumerated are particularly rare : I have added at the
end of the work a list of such of them as are considered least
W