Natural History of District of Columbia — McAfee 87 



Seven-tenths of the distinctive Pine Barren plants, there- 

 fore, occur in eastern Maryland and Delaware, yet there are 

 no Pine Barrens. What is the reason? In considering this 

 point it may be helpful to give a brief picture of the New 

 Jersey Barrens. The soil is sand, one is tempted to say 

 pure sand, loose and shifting where dry, and compact where 

 wet. Gravel occurs in varying degrees being most abundant 

 on the area known as the Plains, where the vegetation is 

 depauperate and favorable conditions for plant growth evi- 

 dently at the minimum. l*oor soils rule, therefore, and with 

 the poorest is associated the climax of vegetational features 

 that have won for these areas the name ''barrens." 



Briefly noting the vegetation beginning with the largest 

 growths, Pinus rigida is the only species, attaining tree 

 stature in the dry parts of the typical Pine Barrens. Cha- 

 maecyparis almost as exclusively occupies a corresponding 

 position in the well-watered places where it is the most im- 

 portant element of the cedar swamps. Over the ordinary 

 surface of the Barrens, however, Pinus rigida reigns supreme. 

 Next to it in stature are four oaks: Quercus nutrHandica, 

 Q. stellata, Q. prinoides and Q. iUcifolia. 



A conspicuous characteristic of the undergrowth is the 

 tendency of the species to occur in colonies. In the diier 

 parts, here Arctostaphylos uva-ursi mats the surface, there 

 Dendrium hiixifoJium monopolizes a space, or it may 

 be Hudsonia ericoidcs, GaitUheria prociDnhcns. Kuhnia 

 angustifolia or Gaylussacia or Vaccinium. In wet places 

 Chamaedaphne calyculata, alder, clammy azalea, and Rhus 

 vernix are conspicuous. The actual floor of the Barrens in 

 dry sandy areas abounds with Cladonia and in the wet spots 

 with sphagnum and Sarracenia. On wet bare sand grow the 

 characteristic species of Lycopodium and that greatest treas- 

 ure of the Pine Barrens — the little curly fern, ^chizaea 

 pusilla. 



Obviously the predominant elements of the Pine Barren 

 flora are plants that either prefer the so-called poor (pre- 

 sumably acid) soils, or that find sanctuary in soils in which 

 competition with the plants of neighboring areas is greatly 



