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 Interim (Horned Poppy), Euphorbia par alias (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 oecological 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 Zoster a 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. 
