292 Proceedings Port. Soc. Nat. Hist. 



Group V. CAEOLI^^IAX Plaints 

 This small groiij) of southern species — 3 per cent of the 

 native flora of the eastern Penoliscot Bay region — affords 

 nearly as much phytogeographical interest as do the sul)- 

 arctie types. These Carolinian plants, although of southern 

 oriffin, are distinct from the Alleuhanian. Thev are char- 

 acteristic of the Cretaceous and Tertiary sands and clays of 

 the Xew Jersey Pine Barrens and other portions of the At- 

 lantic coastal plain. This coastal plain flora extends north- 

 ward from the Gulf of Mexico along the coast to jSTew Jersey 

 and thence, in less pronounced development, to Staten Island, 

 southern Long Island and southeastern Xew England, with 

 arms running up the larger river valleys. 



The presence of typical coastal plain species growing on 

 granite rocks or the scantiest of soil on the Maine coast af- 

 fords interesting speculation as to their geographic origin, 

 the nature of which will be discussed later. The occurrence 

 of Carolinian plants in such habitats, however, is not unique, 

 for several coastal plain plants have long been known on 

 quartzite rocks in the Kittatinny ]\[ountains of jSTew Jersey.' 

 These ([uartzite rocks and the granite hills of Penobscot Bay 

 furnish a soil which, like that of the sand plains along the 

 coast, is very rich in silica and so is acid rather than basic. 

 (See page 202, 'Note 2.) 



It has been argued that species which are restricted to 

 these acid soils are able to utilize the silica in some way as 

 food and the term ''silicophiles" has been aj^plied to them. 

 Contejean,' Hilgard' and others have shown, however, that 



1. Britton. On the Existence of a Peculiar Flora on the Kittatinny 



Mountains of Northwestern New Jersey. Bull. Torr. Bot. 

 Club 11: 126-128 (1884). Note on the Flora of the Kittatinny 

 Mountains. Ibid. 14: 187-189 (1887). 



2. Contejean. De I'lnfluence du Terrain sur la Vegetation. Ann. 



Sci. Nat. Bot. V. 20: 266-304 (1874); VI. 2: 222-307 (1875). 



3. Hilgard. Soils, pp. 521-522. New York. 1911. 



