THE FLORA OF MISSISSIPPI. 165 



Ipomoea Pes-Caprae, Strophostyles helvola, 



Ipomoea acetosaefolia, Panicum amarum, 



Panicum halophilum, Uniola paniculata, 



Iva imbricata, Daubentonia longifolia. 



Upon the higher sand ridges and dunes a little back 

 from the beach are found the following : 



Pinus taeda, Sabal minor, 



Pinus australis, Serenoa serrulata, 



Quercus geminata, Ilex vcmitoria, 



Quercus Virginiana, Myrica cerijera. 

 Cladonia rangiferina, 



In and bordering salt marshes are the following species: 



Baits maritima, Dondia maritima, 



Salicornia biglovii, Limonium Nashii, 



Avicennia nitida, Leptilon Canadense, 



Euphorbia polygonijolia, Crantzia lineata, 



Lippia nodiflora, Atriplex cristata, 



Xyris serotina, Hydrocotylc repanda, 



Utricularia subtdata, Hydrocotylc interrupta. 

 Lithophila vermiculata, 



A few observations may be briefly noted from the fore- 

 going discussion. Two widely separated regions of the 

 State, wide apart both in topography and physical as- 

 pects and in distinctive floral features, are the northeastern 

 hills in the immediate vicinity of the Tennessee River and 

 the flat coastal pine barrens. These two regions have 

 each a comparatively large number of species peculiar to 

 the region, in the one case, species characteristic of rich 

 shaded northern hills, in the other, of wet barren sand 

 flats, that are southern in distribution. The nearest ap- 

 proach to the pine barrens flora of the south (which in- 

 cludes the pine barrens flora of New Jersey) is the bog 

 floras of the northern glaciated regions. Just what is 

 the significance of this parallelism has not yet been satis- 

 factorily explained. General similarity of soil conditions 

 may be sufficient to explain the persistence of these pe- 

 culiar floras in those particular situations, but doubtfully 

 accounts for their origin in such widely separated areas. 



