50 VEGETATION OF BLAKENEY POINT. 



Senecio Jacobaea (v.c.) 



Sherardia arvensis (v.r.) 



Stellaria Boraeana (c.) 



Taraxacum erythrospermum (f.) 



Valeiianella olitoria (c.) 



Veronica arvensis (f.) 



officinalis (c.) 

 General Characteristics. 



The chief feature exhibited by the dune vegetation here, as 

 elsewhere, is the reduction to a minimum of water evaporation 

 from the leaf surface by various transpiration checks. Of the 

 various forms which these assume, most types are represented 

 by the Blakeney flora, and the absence of less protected species 

 on the more stable parts, such as Viola ericetorum and Tri folium 

 repens, which are frequent constituents of arenicolous floras 

 elsewhere, is perhaps associated with the combination here of 

 great exposure with the adverse conditions of the soil itself. 

 The rolled type of foliage is represented in the Marram grass, 

 Triticum, Festuca arenaria, Corynephorus, and Galium verum, 

 whilst the succulent type, with abundant water-storage tissue, 

 finds examples in Cakile, Arenaria, Salsola, and Sedum. By 

 far the commonest transpiration check, however, is that furnished 

 by the rosette type of foliage, which, whilst it admits of the 

 maximal amount of assimilation, places the leaves in the plane 

 of greatest humidity and their stomatal surfaces against the 

 damp substratum. 



The rosulate habit is frequent amongst the ephemerals, being 

 found in Cerastium, Erophila, Myosotis, and Valerianella. 



Amongst the biennial and perennial species this habit is 

 found, either exclusively or during the vegetative period only, 

 in Armeria maritima, Carduus arvensis, C. lanceolatus, 

 Convolvulus Soldanella, Erodium cicutarium, Geranium 

 molle, Hieracium Pilosella, Hypochteris glabra, H. radicata, 

 Plantago Coronopus, Rumex acetosella, Silene maritima, and 

 Taraxacum erythrospermum. 



The close contact of the leaves with the soil in many of these 

 rosettes is perhaps better illustrated by Erodium than any 



