74 REPORT OF NEW JERSEY STATE MUSEUM. 



there are in the Middle or West Jersey districts certain "Pine 

 Barren" islands, where a number of characteristic Pine Barren 

 plants occur, often associated with species of wide range or others 

 typical of the Middle district. One of the most important of 

 these is the so-called Sandhill region of Middlesex Co., while 

 Griffith's Swamp (now destroyed) near Lawnside, Camden Co.^ 

 was famous in the past. Prof. J. B. Smith has indicated several 

 of these islands in his map (Ann. Rept. N. J. State Museum for 

 1909), but they do not seem sufficiently well marked or equal in 

 character to warrant such recognition. 



There seems to be no peculiar geological formation correlated 

 with these outlying colonies except that dry ground species are 

 found where deposits of pure white sand or gravel occur, but 

 which are not necessarily of the same age as similar deposits in 

 the Pine Barren area proper. 



Intrusions of the Middle district flora into the Pine Barrens in 

 the form of narrow^ tongues along the boundary line have al- 

 ready been alluded to, but there are also occurrences of similar 

 species well within the region, where extensive clearings have 

 been effected and maintained for long periods of years; such 

 occurrences can, I think, be safely regarded as intrusions from 

 the Middle district, analogous to the occurrence of weeds in all 

 spots that are brought under cultivation. 



The attempts that have been made to list the typical plants of 

 the Pine Barrens are in some respects as misleading as the efforts 

 to outline the district, due, of course, to the fact that the writers 

 were only familiar with a portion of the region or were relying 

 entirely upon compilation. 



Dr. Britton's list of fifty Pine Barren species* comprises 

 twenty-five that are as common in the Middle district as in the 

 Pines, and six that are distinctly Middle district species and do not 

 occur in the Pine Barrens — Desmodium viridiftorum, Phlox sub- 

 ulata, Qncrcus phellos, Sfipa avenacca, J uncus scirpoidcs, Bleo- 

 charis melanocarpa. 



Rev. Mr. Lightpipe's listf contains the following, which are not 

 found at all in the Pine Barrens, or are verv rare : Onoclca scusi- 



*Bull. Torn Bot. Club VII., p. 82; XL, p. 126. 

 t Torreya II., p. 79. 



