MARITIME ASSOCIATIONS 279 
and constituting an edaphic modification of the ordinary 
reed-swamp. The dominant plants are Juncus Gerard, 
Scirpus maritimus, Glyceria maritima, and in some parts 
Phragmites communis also. Where the soil is drier the 
plants are not so tall-growing as in the reed-swamp ; this 
type may be called a salt-meadow. 
Characteristic salt-marsh plants are: Aster Tripolium 
(sea-aster), Statice Limonium (sea-lavender), Armeria mari- 
tima (thrift), Plantago maritima (sea-plantain), Salicornia 
herbacea, Spergularia salina (sea-spurrey), Sweda maritima 
(sea-blite), Atriplex portulacoides (sea-purslane), Artemisia 
maritima (sea-wormwood), Beta maritima (sea-beet), 
Triglochin maritimum (seaside arrow-grass), Cochlearia 
officinalis, C. anglica, and C. danica (scurvy-grasses), 
Glaux maritima (sea-milkwort), Atriplex littoralis (grass- 
leaved orach), Scirpus triqueter, S. rufus, Hordeum mari- 
timum (sea-barley). 
2. Flora of Sandy Shores.—On sandy shores the con- 
ditions are quite different from the salt-marsh. Except 
within reach of the tides, the amount of salt present in the 
soil-water is comparatively small. The porous soil allows 
rain to drain away very rapidly, and the plants are sub- 
jected to long periods of drought. The xerophytic 
character of the plant, therefore, is not due to physiological 
dryness, but to physical. Yet the adaptations are the 
same in both cases—succulent plants are as common here 
as in the marsh ; indeed, some are found in both situations 
—e.g., thrift, scurvy-grass, sea-plantain, and beet. 
Where strong winds prevail in a direction at right angles 
to the coast the sand is blown inland, and accumulates in 
long sand-hills or dunes running parallel to the shore. 
Unless the dune is completely covered with vegetation— 
and this is rarely so—the sand is carried still farther inland, 
and a second or even third line of dunes arises on the 
landward side. The flora of the dune varies according to 
the compactness of the sand, and to some extent according 
to its chemical composition. Most of the sand consists of 
quartz-particles, and the soil is consequently very sterile, 
but when the remains of marine shells are present the 
soil is richer, and many calciphilous plants occur. 
On the sand immediately above the mean high-water 
mark, and only covered at very high tides, a narrow zone 
of strand-vegetation occurs. The water within reach of 
