204 



BOTANICAL GAZETTE 



[SEPTEMBER 



extent during the remainder of the season, the fluctuations being 

 markedly greater than in the other associations. 



With the fixation of dunes and the increase of grasses and other 

 herbaceous vegetation, seedlings of conifers develop and give rise 

 to an evergreen forest association succeeding the cottonwood, and 

 here designated the pine dune association (fig. 7). This associa- 

 tion varies somewhat in composition in different localities, but 

 in the area under consideration is dominated by Pinus Banksiana, 



• 



Fig. 7. — Dune with Pinus Banksiana, P. Strobus, Juniperns communis, etc.; 

 station 6; Miller, Ind. 



associated with Juniper us virginiana, J. communis, and in older 

 portions with Pinus Strobus. In the undergrowth Arctostaphylos 

 Uva-ursi is conspicuous, associated with Rhus canadensis, R. 

 toxicodendron, Primus virginiana, Celastrus scandens, seedlings of 

 Quercus velutina, Smilacina stellata, Asclepias tuber osa, Monarda 

 punctata, and other woody and herbaceous plants. It is evident 

 that this association is unique in the dominance of evergreens, 

 while its limited extent shows that it is comparatively short-lived, a 



