245 
The Bouche d' Erquy in 1907. 
annual Suceda marilima is thickly scattered through the Glyceria- 
turf; the Salicornia-flats, crimson in colour, bearing a dense and 
uniform covering of S. lierbacea ; finally the shallow channels and 
depressions that occur most characteristically among the Suaeda- 
hillocks and which are remarkable as being the principal habitat of 
the distinct apple-green form of 5. herbacea. 
These associations, being largely composed of plants renewed 
each year by seed, afford excellent subject-matter for the study of 
the influence of climatic and other physical factors upon plant- 
populations. In the general features of their distribution, though 
.A 
subject to minor oscillations, these associations shew a remarkable 
persistency. But when the annual Salicornia- and Suaeda- 
constituents of the associations are analysed in detail, and the 
results of successive years compared, indication of extreme 
instability is manifest. The most striking instance of this instability 
is afforded, perhaps, by the “ apple-green ” Salicornia-depressions 
and channels. In 1904 and 1905 they fully merited the name of 
apple-green and stood out prominently from the purple and crimson 
vegetation round about. In 1906 a large infusion of crimson and 
dingy coloured Salicornias was mingled with the green, so that the 
channels had lost their distinctive character. The dingy specimens 
included several shades which tended to connect the reds with the 
greens. In the present year the channels shew a combination of 
the features of 1905 and 1906. As in 1906, both red and green 
Salicornias are present, but they shew an extreme purity of colour 
(recalling 1904 and 1905) and the dingy intermediate forms were 
much more rare. 
On the Suseda-slopes a somewhat analogous change was 
noted. The zonation of former years into purple and green Suaedas 
has largely disappeared and a colour mosaic has taken its place. 
Moreover the Salicornias, which always accompany the Suaedas in 
this association, and which in the past largely consisted of dingy 
individuals, shew this year a striking infusion of apple-green forms. 
Thus each year brings its surprises, and it is impossible to say 
what fresh chromatic combination may be next revealed. This 
much at any rate is certain, that we are only just beginning to 
appreciate the full complexity of the phenomena, the causes of 
which we would elucidate. 
In the report for 1906 some mention was made of an extensive 
series of reciprocal transplantations carried out to ascertain whether 
the differently coloured forms breed true from seed, 
