THE COAST-FLORA OF THE CLACTON DISTRICT. 200
repens, Hordeum maritimum and Arundo phragmitis. The
salinity is very considerable in some places, judging by the
succulence of certain leaves, which attained a thickness of quite
two millimetres (Beta, Atriplex portulacoides). Rarely a Sali-
cornia may be found showing the interesting phenomenon of
having lost its succulence, except in a few internodes of the
stem. Luxuriant colonies of Atriplex littoralis accompanied by a
particularly leafless form of Polygonum aviculare cover some sea-
walls near Stone Point.
Other plants growing with preference on the cliff, though
their connection with salt is doubtful, are Solanum dulcamara,
Rubus fruticosus (Bramble), Reseda luteola (Weld or Yellow-weed),
Smyrnum olusatrum (Alexanders), Pastinaca sativa (parsnip),
Sedum acre (Wall-pepper), Helminthia echioides (Ox-tongue), etc.
On the loose valley-gravel cliff, I have not observed any
halophilous plants. The vegetation is mainly composed of
species from the land above, weeds of cultivation, meadow grasses.
Besides these, plants with good seed-dispersal apparatus and a
capacity for holding the soil together, such as Tussilago farfara
(colts-foot), Epilobium hirsutum (codlins-and-cream), Equisetum
telmateia (in wet places), form what may be described as a land-
slide vegetation.
Mr. Shenstone, in his short account of the Essex coast-
flora, mentioned the fact that certain littoral species occur on
high mountains. Such is the case with Armeria vulgaris, Silene
maritima, Plantago maritima and Pl. coronopus (which are
obviously closely related to Pl. alpina) and Cochlearia officinalis.
(Ecologically this is not difficult to understand. The absorp-
tion of water is as difficult in the cold soil of high mountains as
on the saline soil of the shore. The action of wind is strong in
both cases, and rapid alternation of temperature causes in both
cases rosette-formation. How they are connected historically,
I cannot venture to say ; it seems probable that the coast-plants
are relics from the glacial period, more or less modified.
It is remarkable that most true halophytes belong to a few-
families, notably the Chenopodiaceae, Cruciferae, and Graminae.
Many of our edible vegetables are descended from halophytes,
e.g., beet-root, celery, cabbage, kale, spinach, horse-radish ;
some of the commonest weeds are also halophilous, e.g., Orachs.
This fact might find an explanation in the occurrence of a con-