206 THE COAST-FLORA OF THE CLACTON DISTRICT.
nations of temperature, which doubtless occur in this sandy
soil. Some other species whose position seems not so well
defined, and which besides, are rare on the Clacton coast, are
Glaucium luteum (Horned Poppy), Euphorbia paralias (Sea
Spurge), Filago minima (Field Filago). The grey dune merges
often imperceptibly into the higher littoral meadow, of which
I shall speak later on.
II. PELOPHYTES.
I have dealt with the ecological factors, mud, salt and wind,
whose action determines the morphology of the mud-loving
plants. Besides those characteristics which may be explained
by the physiological dryness of the soil there are one or two
others. All pelophytes are glabrous, at any rate all those that
are covered frequently by the sea-water ; they may thus be
protected somewhat from being choked by the mud. The
deposition of mud may also tend to simplify the form of the
plant. Leaves and complicated flowers disappear ; Salicornia
is the most perfect type of mud-plant. The same deterioration
is favoured also by the movement of the water ; but it is in-
teresting to note that it is less due to chemical action of salt
than to the mechanical influence of mud-deposition and tidal
scour. Aster tripolium (Sea Aster) illustrates the deteriorating
influence of the muddy, tide-swept stations very well. When
exposed to the full force of the scour and consequently submersed
twice every day for a considerable time, it is low, very succulent,
small-leaved without the blue ray-florets of its composite blossom.
In the sheltered creek it becomes erect, often two feet high,
so that its corymb may be kept as long as possible out of the
water,2 whereas in higher stations it becomes again low and
straggling, but has large thin leaves, and bees may be seen
swarming round its pretty flowers, in which the blue ligulate
florets are numerous.
The pelophytes occur in several zones :
1. Below the low-tide limit grows in company with a
number of sea-weeds Zostera marina (Grass-wrack).
This zone is purely hydrophytic.
2. The open vegetation in muddy creeks and basins
daily submersed by the tide and exposed to tidal
scour.
2 The flowers with very few or no florets.