VEGETATION OF BLAKENEY POINT. 
523 
these latter is removed and only the more robust of the St at ices 
survive the ensuing struggle; these from their perennial character 
may remain for a considerable period of years, and by virtue of 
the two inches of soil in which they grow, will be better 
nourished and therefore larger than those of the flanks which 
are rooted in bare or nearly bare shingle. The increase in size 
of those overwhelmed by the main bank may be due to one of 
two causes, or even more probably to a combination of both. 
The shingle, when it submerges the crest in this way, kills 
most of the plants that it covers, so that such survivors as 
remain are freed from the competition of others, whilst, being 
still rooted in the soil below, they retain all the advantages of 
nourishment. 
The shingle may further act as a mulch to the bnried soil and 
so increase its water-retaining powers. 
Those plants which were dug up shewed few or no lateral 
roots except in the soil beneath and in the top layers of shingle, 
where soil or humus had collected, and this would appear to 
negative the idea that the shingle is of value per se." 
III. The Dune System. 
The dunes at Blakeney form three separate groups, situated 
in each case upon a foundation of shingle derived from a 
complex of crowded and anastomosing laterals arising from the 
main shingle bank. By far the largest of these groups, some 
100 acres in extent, occupies the region which we call the 
Headland, and comprises a series of successive ranges of dunes 
roughly parallel to the main axis of the bank. From near the 
eastern extremity of this main system, but not in actual 
connection with it, a narrow series of dunes extend in a 
south-westerly direction lor about one-third of a mile. They 
are low in height, and more densely clothed than those of the 
Headland, from which they are distinguished by the name of 
the “ Long Hills ” (see map, fig. 1). The third dune group is 
14 One minor point may he mentioned here with regard to t lie duration of 
Planlago Corouopus ; this is given in most of the Floras as either doubtfully annual 
(Babington, 9ih ed., H. and J. Groves, p. 347) or as either annual or biennial 
(Hooker, p. 289). There is no doubt that the plants at Blakeney are in some cases 
several years old. as the remains of successive leaf rosettes testify, besides actual 
cultural experiments. 
