SEAWEEDS AND THE WATER-FLORA. 1 93 



tufts of Ammophila. Still further from the sea, Lotus 

 corniculatus^ Vetch, Potentilla anserina^ and many small 

 herbaceous plants are able to fix themselves. A great 

 number of mosses Hypnum cuspidatum, H. squarrosuni^ 

 species of Hylocomium and Liverworts, form dense tufts 

 between the other plants, or in some places crusts of 

 Cladonia and other lichens cover the sand. The change, 

 however, generally ends in the production of the 

 peculiar "golfing" turf, only found in perfection near 

 the seaside. At Southbourne (England) the herbaceous 

 plants are not the same as those that are found on the 

 sands in Ayrshire. Both Viola canina and Jasione 

 montana are remarkably common, and Furze or Whin, 

 Heather, and even Pine trees, seem able to occupy the 

 sand dunes, as soon as they have become definitely 

 fixed. It is of course well known that in France, the 

 great damage causeci by blown sand and wandering 

 dunes has been prevented by artificial planting with 

 Pine trees. Even in Ayrshire, Pinewoods occur in 

 country which seems to have been at one time pure 

 sand hills. At present, every stage can be traced 

 between the ordinary arable land or pasture and the 

 sand only covered by tussocks of Ainnwphila. 



Mud-Flora. — The conditions when mud or fiat sandy 

 soil forms the coastline are exceedingly complex 

 and difficult. There are id) Submerged Seagrasses which 

 occupy the shifting banks of mud and sand, and are 

 only visible at low water, {b) Muddy Flats and gentle 

 slopes only covered at high water and colonised by the 

 Cochlearia or Scurvy-Grass-Association, {c) Lagoons and 

 deeper places near the shore, however formed, inhabited 

 by the Estuarine Reeds. The Seagrasses occupy the 

 deeper water, and there is probably a distinct series of 

 forms leading from {b) and (r) to them ; but it is not 



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