3(U BOTANICAL SURVEY OF DISMAL SWAMP REGION. 



heads of bayous, but rarely makes a dense growth to the exclusion of 

 other speeies. 



Baccharis- Hibiscus association. — A number of speeies are most at 

 home in the wet soil at the inner edge of the salt marshes, whence 

 they stray out into the Juncus roemeriunus or other associations. 

 Most important of these is Baccharis halimifolia, a handsome shrub 

 usually 1^ to 2£ meters (5 to 8 feet) high. In the fall this plant is 

 one of the showiest in the region, its snow-white pappus making a 

 brilliant contrast to the dark-green foliage. 1 No less beautiful is 

 Hibiscus moseheutos (locally, "wild cotton") with its large whitish or 

 deep rose-colored flowers, a species very characteristic of the marsh 

 borders. Solidago sempervirens is abundant. Only occasional in 

 Virginia, although common farther south along the coast, is the sea 

 ox-eye (Borrichia J'nitcsccns), an interesting, Ilelianthus-like com- 

 posite, with straggling stems o to •'» decimeters (1 to l> feet) long and 

 thickish leaves, whose exceedingly dense covering of hairs gives a glis- 

 tening appearance to the seemingly smooth surface. The large clumps 

 of Panicum virgatum, "switch grass," are sometimes a conspicuous 

 feature of the marsh borders. Kosieletzkya virginica, a malvaceous 

 plaid, with showy rose-purple flowers, is frequent and characteristic. 

 WUlugbacija (Mikania) scaurfeus, Rumex re rile Hiatus, Pluchea cam- 

 phorata, and Atriplex Jiasfata are less important. 



The small marshes which occupy depressions among the sand dunes 

 contain, as would he expected, some species that are normally salt- 

 marsh plants. The greater part of their vegetation is composed, how- 

 ever, of fresh marsh and of sand-strand species. For convenience, 

 they will be described under the head of "Sand-Strand." 



The general aspect of the salt-marsh vegetation is somber and 

 monotonous, despite the occasional presence of bright-colored flowers. 

 This is due to the overwhelming predominance of a few species of 

 reed-like and grass-like plants. Especially from autumn to early 

 spring, when most, of these are discolored ami brownish, the color 

 tone is a dull one. 



ADAPTATIONS TO ENVIRONMENT IN THE SALT-MARSH VEGETATION — 



LIFE FORMS. 



In regarding those conditions of the physical environment which 

 most probably affect, the structure and habit of salt-marsh plants, three 

 points present themselves at once. These are: 



1. Liability to partial submersion at high tide. 



2. A soft, more or less mobile substratum. 



3 The presence of a relatively high percentage of common salt 

 (sodium chloride) in soil and water. 



1 Although perhaps best developed at the edges of salt marshes, this plant is 

 abundant in other situations, as along roadside ditches, sometimes at a considerable 

 distance from salt water. It is also common among the dunes, in moist pine woods 

 behind them, etc. It seems to be more dependent upon sea air than upon saline soil. 



