512 
VEGETATION OF BLAKENEY POINT. 
purposes of reproduction, and even so occasionally suffer 
considerably in consequence . 10 
It is worthy of note that only those species attain any degree 
of frequency which in one way or another are adapted to the 
strenuous conditions which characterise this class of habitat. 
It is not in the scope of the present paper to treat in detail 
of the cryptogamic flora, but before leaving the main bank it 
may be said that where extreme stability obtains, as in the 
shelter of the dunes or on the barer shingle of the lateral hooks, 
lichens are of frequent occurrence. Of these the more im- 
portant pioneer species are Buellia colliideus and Rhizocarpon 
confervoides which are most frequently followed by Lecanora 
atra and Physcia parietina. 
II. The Lateral Hooks. 
As the flora of the lateral banks will be treated with 
greater detail in another connection, we shall only give here a 
general account summarising the observations on all the banks. 
Whilst the main bank is essentially a shifting formation, 
the laterals, though belonging to the same class, are relatively 
stable, and associated with this greater fixity we find not only 
that colonisation has proceeded much further, but also the 
somewhat indefinite character of the distribution on the main 
bank gives place to a much more clearly marked arrangement. 
No fact could emphasise this more than the repetition on each 
of the successive banks of the same sequence of zonations ; so 
that, in general, an examination of any single hook gives 
broadly the essential features of all. 
Viewed from the aspect of their conformation we can dis- 
tinguish three main parts consisting, respectively, of the sloping 
sides (these are steeper on the face directed towards the free 
end of the main bank and usually very gentle on the opposite 
face) ; the crest, forming a flattened or slightly convex top to 
10. The following is an extract from Professor F. W. Oliver’s field note book for 
July 13, 1909. ■* Rumex— after storm (N.W.) of July 7, most spikes of Rumex 
hanging brown or dead (wind, or wind with salt ?). Those under the protection of 
Suxda frutiCDsa , etc., uninjured. The Rumax was all right on the 6th, so this fixes 
cause of damage.” 
