200 
THE COAST-FLORA OF THE CLACTON DISTRICT. 
whereas the ordinary observer will content himself by stating 
what seems to be the dominant fact. However, the importance 
of water and transpiration in plant-life is so transcendent that 
any amount of chemical analyses and. microscopical research 
can do no more than amplify and render more precise the notions 
got by ordinary observation. 
The study of the sea-shore vegetation, as of any other,, 
falls naturally under two heads: 
1. The floristic study, comprising the classification of the 
species into different associations. 
2. The study of the economy of those species and associa¬ 
tions, naturally subdivided into 
(a.) The study of the cecological factors : light, heat, 
atmospheric precipitation, physical and chemical 
properties of the soil, including water, and 
(i b .) Tire study of growth-forms, morphological and 
anatomical peculiarities which must be regarded 
as adaptations to the action of the cecological factors 
mentioned. 
The order in which I proceed is, perhaps, not strictly scientific; 
I shall treat first of the prominent oecological factors, soil, 
water and salt, and then describe the various associations, 
floristically and morphologically. 
The soil of the coast is of two kinds : (i) sandy or gravelly 
soil, occurring both on the valley gravel cliff from Clacton to 
Holland and on the foreshores and low dunes on the coast stretch¬ 
ing from Clacton to Colne Point and further. The particles 
composing this soil being large and loose, its power of retaining 
atmospheric precipitation is as small as its power of raising 
water from moister subsoils. It is well aerated. In the sun 
it is heated easily, but loses its warmth as easily at night: in 
no soil are the alternations of temperature so pronounced 
as in sand. The particles are small enough to be carried away 
by the wind ; we observe the beginning of a dune at various 
places. Chemically the nutritive value of a pure sand is 
lowest of all soils. Sand mixed with gravel is not mobile, but 
more liable to be heated. On the cliff it forms an extremely 
unreliable support for plant-life, and is providing continually 
new surfaces by crumbling down. When artificially supported 
bv a sea-wall, or the plantation of Tamarix, it becomes more 
