398 Annai-s of the Carnegie Museum. 



Lobelia kalmii, Hieracium canadense. 



Aster polyphy litis, GnaphaUum deairrens, 



Artemisia canadensis, Argentina anserina, 



Pruniis piimila, Pntnus pefinsylvanica, 



Finns stroluis. 



B. Species the range of which is southern — Carolinian, or extend- 

 ing also over other areas of the austral (austroriparian or gulf strip). 

 Total 42 species. 



Typical representatives of this group are : 



Lycopodium alopecuroides, Hemicaipha niicranflia, 



Magnolia acuminata, Liriodetidron tiilipifera, 



Blephariglottis perama'na, Ptelea trifoliata, 



Hypericum drummondii, Sabbatia angtilaris, 



Asclepias tuberosa, Lithospermum gmelitii, 



Lycopus rubellus, Galium pilosum, 



Gnaphalitim purpureum. Sassafras sassafras, 



Nyssa sylvatica. 



C. Species the range of which with respect to the position of Presque 

 Isle is neither definitely northern nor southern. Species generally 

 ranging over both Carolinian and Alleghanian areas. Total, 283 

 species. 



From the above grouping it appears that, taken as a whole, the flora 

 of Presque Isle is more distinctly northern than southern, and in a 

 general way may be termed Alleghanian, although the greater majority 

 of the species are not closely restricted to either class. It is of interest 

 to note in this connection that Todd, in his studies on the Birds of Erie 

 and Presque Isle,®* says: "The region under consideration [Presque 

 Isle] may safely be considered as included within the Alleghanian 

 Fauna, although with a slight admixture of the Carolinian element." 



Transeau has pointed out that in eastern North America there may be 

 distinguished four great forest centers, each center having peculiar to it a 

 forest the species of which attain there their best development, thinning 

 out from the region in all directions.®^ These centers are : " (i) the 

 Northeastern Conifer Forest, centering in the St. Lawrence Basin, (2) 

 the Deciduous Forest, centering in the lower Ohio basin and Piedmont 



8«Todd, W. E. Clyde. "The Birds of Erie and Presque Isle, Erie County, 

 Pennsylvania." Annals Carnegie Museum, IT : 497, 1904. 



*' Transeau, E. N. "Forest Centers of Eastern America." Atn. Nat., 39: 

 875-889, 1905. 



