VIIl] 



SAND DUNES 



137 



with its xerophytic specialisation, that makes it before 

 all other plants the leading builder of Dunes. Other 

 grasses take part also, for instance the Lyme-Grass 



Fig, 24. Horizontal rhizome of Marram Grass, showing three nodes, 

 from which roots arise. From two of them leafy buds have grown 

 upwards through the sand. The arrow points towards the apex 

 of the rhizome. 



