212 THEO. J. STOMPS 



one of the sand-reed-grasses, wherever it seemed necessary and 

 natural vegetation was only sparingly present. The resultant 

 impression is one of artificial rather than of natural vegetation 

 in our dunes. In the dunes of Lake Michigan, however, nothing 

 of the kind is seen and nature rules supreme. This especially 

 makes the study of this dune region so extremely interesting. 

 Nowhere can the formation of new dunes and the encroachment 

 of the dune-complex on pre-existing plant-societies be better 

 studied. 



Seen from the beach our Dutch dunes offer a rather monoto- 

 nous aspect. A low row of sandhills, almost equal in height and 

 covered on their slopes and crests by tufts of the sea marram, 

 extends all along the shore. Formation of embryonic dunes cer- 

 tainly takes place on the windward slopes of these shore-dunes, 

 but in a very slight degree. As sand-accumulating species only 

 some of the above named halophytic beach-plants can be men- 

 tioned, especially Agropyrum junceum and Honkenya peploides 

 and besides these Cakile maritima and Convolvulus soldanella. 

 The sand, that is blown landward is completely captured by 

 the plantation of A?nmophila on the foremost row of dunes. 

 In binding the sand still other species are concerned, as Elymus 

 arenarius, Agropyrum pungens, Festuca rubra, Sonchus arvensis, 

 Glaucium luteum, Eryngium maritimum, Cakile maritima, Sal- 

 sola Kali, Convolvulus soldanella, Atriplex littoralis and several 

 other inhabitants of the Ammophiletum. Thus it will readily be 

 understood that it is altogether out of the question that actively 

 moving dunes could originate in my country. Not even do the 

 fore-dunes grow considerably in height, because exceptional high 

 storms take as much sand back to the sea as has been heaped 

 up during a long period. Consequently, when one looks towards 

 the interior from the top of a shore-dune, one sees an undulating 

 country, here and there three miles broad, covered by vegetation 

 all over. Some dunes are overgrown with thickets of Hippophae 

 rhamnoides, others with Salix repens, others again with a dense 

 carpet of mosses and lichens, the most important of which is 

 Barbula ruraliformis, Near the horizon the eye may discover a 

 line of wood, the border of human plantations on the oldest 



