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SEA-SIDE PLANTS.
BEING THE SUBSTANCE OF AN ADDRESS DELIVERED
AT CANVEY ISLAND, JUNE 15th, 1901.
By PROF. G. S BOULGER, F.L.S., F.G.S., V.P.E.F.C.
Although not myself a total abstainer, I can feel for the
inhabitants of this island, animal and vegetable alike, who may
be said, in the words of the poet, to be surrounded by
" water, water everywhere,
Nor any drop to drink."
As we have walked along the sea-wall and beach we have noticed
a variety of flowering plants, members of several widely differing
Natural Orders, which agree in the common property of succu-
lence, succulence both in stem and leaf, accompanied for the
most part by a smooth surface, and in some cases by a blue-
green waxy "bloom." The Marsh Samphire or Glass-wort
(Salicornia herbacea), the Sea-blite (Sineda maritima), and the Crab-
weed (Atriplex portulacoides), which grow on the "saltings,"
where they are overflowed at high tide, are, it is true, members
of one Order, the Chenopodiaceae; but the Yellow Horned Poppy
(Glaucium flavum), the Stone-crop (Sedum acre), which we found
so luxuriant, the Sea Sandwort (Alsine marina) and the variety of
the Carrot (Daucus carota, var. gummifer), which occur a little
farther inland, belong to very diverse groups; yet all agree in
these outward characteristics, as do many other sea-side plants,
such as the Sea-Kale (Crambe maritima), which we have not come
across to-day. If we examine the structure of these plants
microscopically we shall find that this succulence is largely pro-
duced by a thick, almost leathery outer wall to the epidermal
cells and the presence of a large amount of water (salt-water) in
the internal cellular tissue, while it is accompanied by a very
small number of stomata or transpiration-pores. This thick
impermeable cuticle and this internal store of water are precisely
similar to the structures that we find in desert plants. We have,
in fact, in these plants growing close to the water's edge special
adaptations to check transpiration, to economise water. Why is
this? A familiar laboratory experiment throws light upon the
question. If we place a thin section of fresh beetroot—a plant
of sea-side origin, by the way—under the microscope and bathe
it with a 5 per cent, solution of salt, we find that the red proto-