129
THE COAST-FLORA OF ESSEX
By J. C. SHENSTONE, F.L.S.
[Being the Substance of an Address delivered at a Meeting of the Club
at Bradwell-on-Sea, on 6th August 1910.]
Our Essex coast offers special facilities for the study
of a branch of plant ecology—the adaptation of plant life to its
natural environment; for, whilst most of the inland areas of
Great Britain afford few spaces where plant-life is unfettered by
artificial conditions, our coast still affords us the opportunity of
studying it almost unaffected by man.
Students of ecology separate plants into two great
divisions :—(1) Hygrophytes, or those which absorb a large amount
of moisture by their roots and transpire it freely through their
foliage, a class including the majority of our British wild-flowers ;
and (2) Xerophytes, or plants which, growing in situations which
do not favour the absorption of water by their roots, transpire
it less freely. Extreme examples of these latter plants may be
seen in the cactus houses at Kew and other Botanical Gardens.
Less extreme examples are numerous in our British flora. The
furzes and heaths of our commons give us examples of plants
growing in sandy situations where water is scarce. In our bog-
flora, we shall find many plants which, owing to the humic acid
contained in water found in such places being injurious to plant
life, have become adapted to absorbing little water by their
roots, while the structure of their leaves has become so modified
as to transpire little moisture during dry weather. It is evident
that the saline condition of the soils bordering upon our sea
coasts and upon the salt steppes of North Europe renders the
absorption of water by the roots of plants growing in such
situations impossible; for otherwise the tissues would very
quickly become choked with salts, and the life of the plant
would be rendered impossible. This latter class of Xerophytic
plants have been named 'halophytes'; and, as our Essex coast
affords excellent opportunities for studying them, they deserve
greater attention than our county botanists have given to the
subject.
To attempt to give details of the structural modifications in
these plants which enable them to flourish under such inhospi-
table conditions would require much more time than our Presi-