Ferns of tlir Disninl Swamp, Virginia. ()3 



ha?! also uuJergone some cliauge on account of its unusual 

 environment. 



Tiie flooded condition of the true peaty swamp floor for several 

 months of the year prevents the growth of ground ferns, except 

 the water-loving woodwardias; therefore all the species of the 

 swamj) proper which grow near the ground occur just above the 

 high-water line and rarely more than three feet above it. 



A systematic examination of the whole swamp for ferns has not 

 been possible, but enough has been learned to show that a number 

 of species have adapted themselves to very unusual conditions, 

 and tiiat some have undergone changes from the normal type. 

 The main factor in determining the character of the pteridophytic 

 life is the flooded condition of the swamp floor for several months 

 annually, but this is less potent now than formerly. 



LIST OF SPECIES. 



1. Botiychium obliqiium Muhl. Oblique Grape Fern. 



On .Tune 10, 1899, I found four plants, growing with other species on logs, 

 at the side of Washington ditch. They were sterile fronds of the previous 

 year's growth. The fronds are less ample and the divisions sliorter, more 

 rounded and more widely placed than in any specimens from about Wash- 

 ington. The dried roots are stronger, blackei", and more abundant. 



2. Struthopteris * legalis (Linn.) Bernh. Royal Fern. 

 O.tiniiiKlii ri'ijidh Linn., Sp. PI. p. lOtio, 175o. 



Ahundant, usually in large rlumps scattered throughout the swamp 

 and always on dead stumps except in the sandy areas. 



In many cases hundreds of dead persistent stipes testify to the great 

 age of the clumps. Just above high-water mark mosses have established 

 a footliold in a broad ring around the old knees of the cypresses, the 

 bends of gum roots, and logs. Various plants, especially ferns, take root 

 in this moss and often reach a large size. The o»ldity and beauty of such 

 growths are striking, especially on a well-preserved knee where the red- 

 disli apex rises several inches above the surrounding moss. (See plate I, 

 Fig. 7.) 



*The ferns usually placed in Osmunda evidently helong to Bernhardi's 

 genus Struthopteris (not Strutliiopterh of authors). The essential features 

 of Bernhardi's description are as follows: 2L Struthopteris mihi. aSV-»o- 

 rrt)i(/<«suhglobosa, bivalvia. E.g. Osmunda regalis. L. — — Cinnamomea. 

 L. — — Claytoniana. L. * * *. Obs. 2. Cane ne Struthopteridem 

 meam cum Struthiopteride Hall, confundas. (Journ. fiir die Botanik, 

 Band 2, 126, 1801.) 



