428 BOTANICAL SURVEY OF DISMAL SWAMP RECKON. 



attractive, with its stems ami leaves bending in graceful curves, espe- 

 cially after a heavy rain. In the wetter parts of the swamp the cane 

 forms small hummocks, with its culms often standing so closely 

 together that it is difficult to insert a linger between them. Tn such 

 cases the dead leaves, as they fall, accumulate among the stems, often 

 to a height of 3 decimeters (1 foot) or more; and, as the strong woody 

 root stocks form a dense sod, one can readily believe that this plant, 

 next to the trees and larger shrubs, is the most effective contributor 

 to the sum total of dead organic matter which year by year accumu- 

 lates upon the surface of the swamp. Arundinaria spreads rapidly 

 by means of its creeping, much-branched underground stems, so that 

 in land recently reclaimed from the swamps and not thoroughly 

 drained it is sometimes a serious pest. 



Woodwardia-Sphaymnn {Fern and Peat Moss) association.— The 

 more open parts of the wooded swamp are not always occupied by 

 Arundinaria or other woody undergrowth. Occasionally a large fern, 

 Woodward lit riiyiniea, predominates, growing usually upon low hum- 

 mocks surrounded by standing water. The fronds often measure 

 more than 12 decimeters (4 feet) from the base of the stipe. 1 Other 

 species often associated with the fern are Eriophorum rirginicuni, 

 Decodon verticiUatus, a suffrutescent lythraceous plant with curving, 

 whip-like stems that strike root and develop aorenchyma where they 

 touch the ground or water, and a handsome orchid, Limodoruni tube- 

 rosum, which here grows to remarkably large size. 



Among the stipes of the Woodwardia, and especially in the shallow 

 water on the margins of the hummocks, a species of peat moss {Spliag- 

 num ciptibifolium ijlaueeseens and its form squamdosa) is abundant. 

 This plant usually has its basal portion submerged, but with a con- 

 siderable length of the stem rising above the surface of the waiter. 

 The longest stems observed were about -H decimeters (H feet), 

 although 15 centimeters (6 inches), or even less, is a more common 

 length. Peat mosses can not be regarded as very important humus- 

 builders in this region, although their value in this regard has been 

 somewhat underestimated. Nowhere are to be seen areas of any 

 considerable size covered with a continuous growth of Sphagnum. 

 Except in some of the ditches of the swamp, 2 these mosses are always 

 secondary members of associations. Of course nothing analogous to 

 the " climbing bogs " and no supplanting of the tree growth by Sphag- 

 num has been observed in the region of the Dismal Swamp. On the 

 contrary, these mosses can make little headway until the forest has 

 been removed or thinned by artificial means. They do not thrive in 



1 For an interesting observation that would indicate positive heliotropisrn in the 

 fronds see W. Palmer in Proc. Biol. Soc. Washington, vol 1:5, p. C>8 (1899). 

 a See under "Aquatic Vegetation," p. 445. 



