646 



PROCEEDINGS OP THE ACADEMY OF 



[Oct. 



viz., Ammopliila arevaria (L. ) Link, Hndsnnia tomentosa Nult,, 

 Myrlca cfrifera L. etc., by three plants, Scirpus debilis L, , Pani- 

 cum virgafum L. and Solidagn ^emperviretis L. If this process is 

 carried still farther, then we have a large number of marsh-loving 

 species appearing in the wet sand of the basin-shaped or elongated 

 depression. The following figure (fig. 3) shows such a dune val- 



Fig. 3. 

 y. Typha Intifolia L.; t. Pure sand ; z. Scirpus debilis Pursh. ; u. Soli- 

 dago seinpervireiis L. ; zz. Euihamia caroliniana (L. > Greene ; k. Myrica 

 cenfera L. ; h. Cyperns nutiaUii Eddy ; w. Aiumophila arenaria (L.) 

 Link ; d. Junnis sp. 



ley, the bottom of which is wet by the seepage of the ground water 

 through the sand. The lower damp, marshy places are covered 

 with a growth of Scirpus debilis L., from which arises Typha 

 latifolia L. and a tall sedge, Scirpus sylvaticus L. The higher still 

 damp areas support Cyperus nuttallii Eddy and Juncus sp., although 

 these two plants are, as a rule, not found in association. The 

 islands, or knolls of sand, which remain in the marshy area are 

 held in situ by Myrica crrifera L., Ammophila arenaria (L. ) Link 

 and Sulidago sempeivirens L. These three plants grow together 

 side by side. Euthnmia caroliniana (L. ) Greene (^Solidngo tenui- 

 folia Pursh. ) is found where the sand is damp. The sand marsh is 



