NEW YORK 



BOTANICAL 



GARDEN 



TORREYA 



Vol. 32 September-October, 1932 No. 5 



Three dune associations compared 



Charles B. Atwell 



Three small dune areas, far distant from each other, afford 

 some worth-while comparisons of their plant life. The first lies 

 along Seven-mile Island off the New Jersey coast about twenty 

 miles north of Cape May; the second on the west shore of Lake 

 Michigan, near Waukegan, Illinois, forty-five miles north of 

 Chicago; the third on the Pacific coast at Seaside, Oregon, 

 twenty miles south of the mouth of the Columbia river. 



On the New Jersey Coast 



Seven-mile Island is a narrow strip having, perhaps, an aver- 

 age width of a half mile and cut off from the mainland by a 

 stretch of salt marshes about three and a half miles wide which 

 is indented with shallow tidal channels and inlets from the At- 

 lantic. The island lies in latitude of about thirty-nine degrees, 

 North; has a summer temperature of 70°-75°F. and a summer 

 rainfall of eleven to twenty-one inches, with prevailing winds 

 from the southwest. The dunes on the island with their plant 

 associations are doomed to disappear in a few years because of 

 the rapid growth of the summer-resort villages, Avalon, Peer- 

 mont and Stone Harbor. The real estate speculator levels the 

 dunes to fill the shallows and marshes and to beautify his prop- 

 erty and so bring it into market. 



The observations upon which these notes are based were 

 made in the summer of 1923. Examination of cross-sections of 

 the undisturbed dune complex which extends along the island 

 from Peermont to Stone Harbor brings out the following facts. 



Along the upper beach and fore dunes, above the ordinary 

 high tide mark, are found frequent clumps of the esculents: sea 

 rocket, Cakile edulenta, and seaside sandwort, Ammodenia pep- 

 loides; while, well above the high water mark, the beach grass, 

 Ammophila arenaria, and the trailing bean, Stropho 'Styles hel- 



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