66 °- ’ , .. The Vegetation of the Sea-coast. 
estuary or even occupying the centre of the river-bed, the outer limit being 
' determined by the average low-water mark. At high tide, only the crowns of 
the trees are visible, the lower parts being under water, but, at low-water, the . 
muddy floor is exposed and the spreading branches and bare trunks are visible. 
Everywhere the more or less limpet-covered, asparagus-like pneumatophores 
rise up in thousands, projecting from the mud for a height of some 20 cm on E 
an average. Some are solitary, but others are more or less bunched together. 2 
Growing scattered amongst them are many young plants of Avicennia of all. 
 sizes, especially near the shoreward margin of the swamp. The innumerable 
erect pneumatophores not only play a biological part, but they strongly oppose 
tidal erosion and in many places, though very slowly, they promote the de 
position of mud and other river-borne matter, until eventually the swamp may 
be replaced by salt-meadow. 
= Leptocarpus-Funcus swamp. 
The Se of Funcus-Leptocarpus swamp differs from that of Mangrove 
in that it is much firmer and less muddy. The soil may be clay, loam, sand 
or mixtures of these; shells of certain molluscs are abundant and the MET. 
is riddled with the holes of crabs') (Heterograpsus crenulatus). 
