378 BOTANICAL SURVEY OF DISMAL SWAM]' REGION. 



The dune marshes. — In small, nearly level tracts or basin-like 

 depressions among the dunes, with a subsoil denser than the surface 

 sand, rain water is often held for days, forming shallow pools; and 

 here the soil, even at the surface, is normally wet. In such places a 

 marsh vegetation finds opportunity for development, and contrasts 

 with other vegetation of the open dunes in that it grows densely, or, 

 in other words, in closed formation. The prevailing species are mostly 

 not halophilo plants, although Sen-pus americanus and Fimbristylis 

 spadieea are often abundant. On the other hand, species normally 

 not halophile, especially two rushes, Juncus scirpoides and J. dieho- 

 tomus, usually dominate the association and give a dull brown color to 

 the whole. Panicum virgatum and Andropogon glomeratus are not 

 infrequent. In the wet sand at the edges depauperate Erigeron 

 canadensis (with thickish leaves), diminutive Sarothra gentianoides, 

 and Diodia virginiana usually occur. Depauperate Myrica bushes 

 frequently occur sparsely. 



Sometimes, as in a marsh at Cape Henry, a considerable variety of 

 inland palustrine species associate together, notably Eragrostis 

 refracta, Lycopodium inundatum, Drosera intermedia-, Fimbristylis 

 autumnalis, Rynchospora eymosa, Centella asiatica, Hydrocotyle 

 umbeUata, etc. South of Virginia Beach a similar marsh contained, 

 in addition to these, Khexia mariana, Eupatorium rotundifoUum, 

 Cyperus haspan, Panicum sphagnicola, P. agrostoides, and cran- 

 berry (Oocycoccus macrocarpus) , the last with stems 2 meters (nearly 

 7 feet) long, creeping among and almost hidden by other plants. 



Such marshes are really part of the fresh-water vegetation of the 

 region, but are placed here for the sake of topographical continuity, 

 and because of the occurrence in them of a few halophile or hemi- 

 halophile species. They form a transition from the sand strand to 

 the salt marsh on the one hand and to the low fresh-water marshes on 

 the other. They may well be termed ''neutral ground." 1 



THE INNER (WOODED) DUNES. 



The high dunes. — These are usually the highest of the dimes, and 

 in most eases bear an open forest of small short-leaf pine (Pinus 

 taeda), usually (> to <.) meters (20 to 30 feet) high and 3 decimeters (1 

 foot) or less in diameter. Sometimes a small growth of deciduous 

 trees and shrubs, notably black cherry (Pr turns serotina), 2 persim- 

 mon (Diospyros virginiana), Xanthoxylum dava-her culls (sometimes 

 G meters, 20 feet, high), Sassafras sassafras, Juniperus virginiana, 



'Massart describes the vegetation of dune marshes along the Belgian coast as 

 "in all things similar to that which inhabits marshes in the interior of the coun- 

 try." Mem. Soc. Roy. Bot. de Belgique, vol. 33, p. 10 (1898). For a reproduc- 

 tion of a photograph of one of these marshes see the same author (loc. cit. , pi. 1 ). 



-The largest specimen observed was about 9 meters (.50 feet) high and 3 deci- 

 meters ( 1 foot) in diameter. 



