44 VEGETATION OF BLAKENEY POINT. 



of which Cladonia rangiferina and Peltigera canina are the 

 most conspicuous. 



Transition Flora. 



The transitions between dune and shingle already referred to 

 are most frequent near the Headland. The dune species are 

 represented by abundant Psamma, together with Senecio 

 Jacobcea and Cerastium semidecandrum, all of which are 

 common. Occasionally Erodium is present, and, more rarely, 

 Carex arenaria. Arenaria peploides is also common, but is 

 perhaps to be regarded as belonging equally to the one type of 

 habitat as to the other. 



The shingle species proper are represented by one plant in 

 abundance, viz., Silene maritima, and the occasional species 

 are Anagallis arvensis, Atriplex patula, and Rumex trigranu- 

 latus. 



Situated near the Lifeboat House is an interesting depression 

 bounded by lateral banks on either side and cut off from the 

 sea by a third ; this is in process of passing into dune through 

 the collection of sand around the low hummocks of Suceda 

 fruticosa with which it is studded. At one point near the edge 

 is a small association of Glaux maritima and Plant ago 

 Coronopus f. pygmcea ; these also occupy in part the channels 

 between the hummocks, suggesting that the association had 

 formerly a much greater extent, but is being driven out by the 

 sand that accumulates above the shallow black mud which 

 forms the soil of these depressions (shingle lows). 



Many of the hummocks are occupied by Silene maritima, 

 whilst their slopes to the channels between afford support for 

 Statice binervosa, from which situation the blown sand is 

 rapidly driving it out. Between the hummocks, besides the 

 plants already mentioned, Poa annua is present in considerable 

 amount, and Frankcenia Icevis is occasionally found. 

 (b) The " Long Hills." 



The " Long Hills " are a more advanced phase in dune 

 fixation than those of the Headland, possessing a more extensive 

 flora and a closer association of its members. As is usual at 

 this stage, which is almost that of the Grey Dune," lichens 



