BRITAIN. 



261 



fruticosa disposes itself in longitudinal belts on the beach corresponding in 

 establishment to periods of dormancy. By its great capacity for rejuvenes- 

 cence and power of arresting the travel of shingle, and thus raising the height 

 of a beach, Suaeda would appear to be preeminently adapted for planting on 

 shingle-spits and similar formations where the object is to arrest the landward 

 travel. A consideration of the occurrence of Suaeda on the Chesil Bank shows 

 that the provision of hxunus is probably of great importance to its welfare, and 

 that in positions where, either from excessive percolation or by tidal restriction 

 on the lee side, this provision is defective, the permanence of the plant is liable 

 to be impaired. In the event of a shingle-beach being artificially afforested 

 to arrest its travel these considerations would have to be borne in mind." 



Oxodion and Silioton 

 CSob-Alpiiie srassland] 



Bare peat 



t 

 RBtrogressive moor 



Cottoa-grass moor 



I 



Oofton-grass and heather moor 



Bilberry moor 

 Healiher and bilberry moor 



Silicion 



• OmdloTi 



MoJiuia Grassland or moor 



Nardus grassland 

 with oiucb.beatbfir 



Nardus grassland 



Oak and bircb scrub 



Oak or birch wood 



■ Siiiclon 



Calcarion 



Retrogressive sc rub 



Fia. 21. 



Ash wood 



Pjpgressivte scrub 

 Calcsu-eous pasture 



Calcareous heath pasture 



\ 



Calcareous heath 



-Relations of communities on siliceous and limestone soib, 

 Peak District, England. After Moss. 



Olweir and Salisbury (1913: 2) have described in detail the habitats and com- 

 munities at Blakeney Point. The general sequence on the shingle is indicated 

 by the zones of the lateral hooks, namely: 



(1) Suaeda jrviicosa zone, (2) Festuca rubra zone, (3) SMice Mnervosa zone, 

 (4) Agrostis maritima zone, (5) the High Elbow. In the Suaeda zone occur 

 also OUone, Aster, and Glyceria, while Triticum, CochUaria, and Atriplex are 



