JUNIPER SWAMP. 423 



abundance of individuals, however, this plant is most important in 

 the lighter parts of the Juniper swamp. 



In some parts of the deciduous or Black Gum forest ferns are abun- 

 dant, especially Woodward iaareolata, Osmundaregalis, and O. cinna- 

 momea. The lizard's tail (Saururus cernuus) is plentiful. 



The most extensive herbaceous growth observed in any part of this 

 formation covers a limited area upon the eastern shore of Lake Drum- 

 mond, where the ground is rather high, firm under foot, and devoid 

 of standing water, at least during the summer. Here the rich, black 

 humus, containing only G percent of inorganic matter, is at leasts 

 meters (10 feet) deep and bears an herbaceous growth such as is often 

 seen in alluvial forests fail her north. Besides a vast number of seed- 

 lings of Acer rubrum, the following perennial herbs are abundant: 

 Saururus cernuus, Boelimeria cylindrica, Polygonum arifolium, Scu- 

 tellaria lateriflora, Aster diffusus, Lycopus rubettus, Eupatorium pur- 

 pureum, Impatiens biflora, and Wood wardia areolata. 



OPEN OK LIOIIT SWAMP. 



Juniper forest association. — This formation, usually known locally as 

 "Juniper .swamp," is most characteristically developed in the periph- 

 eral portions of the Great Dismal and does not extend beyond the limits 

 of the main swamp. On the eastern margin, near the source of the 

 Northwest River, is a typical 1 >ody of such forest. The prevailing tree 

 is the white cedar (Chamaecypar is thyoides), known by the inhabitants 

 of the region as "juniper" (fig. 80). On account of the commercial 

 value of its wood, great numbers of the trees have been removed, and 

 those which remain are mostly small. In places they still form 

 tracts of dense forest, but more often the trees are scattered or mixed 

 with other species. Indeed, extensive areas formerly covered with 

 juniper forest are now almost entirely destitute of trees, and are occu- 

 pied by woody undergrowth, or even largely by herbaceous plants. 

 Such lands are particularly subject to fires, which effectually prevent 

 the renewal of the forest. 



The "Juniper swamp" is usually not so wet as the "Black Gum 

 swamp," yet large areas of it, especially along the Dismal Swamp 

 Canal, are under 3 to G decimeters (1 or -2 feet) of standing water even 

 in midsummer. Without doubt this condition of things is partly due 

 to artificial causes. According to Professor Shaler, Chamaecyparis is 

 most at home in parts of the Great Dismal that are subject to partial 

 desiccation at some period of the year. 



The substratum in the Juniper swamp consists of a red-brown peat 

 composed largely of the stems, leaves, and roots of the Chamaecyparis, 

 and often containing, to a considerable depth, stumps and logs in a 

 remarkably well-preserved condition. This peat often extends to a 

 depth of 3 meters (10 feet) and usually contains small traces of sand. 



2351)2— No. G — 01 s 



