Vol. XIII, pp. 61-70 September 28, 1899 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



FERNS OF THE DISMAL SWAMP, VIRGINIA. 

 BY WILLIAM PALMER. 



The ferns of the Dismal Swamp may be divided into tliree 

 distinct groups according to tlieir place of growth: (1) arboreal 

 species, (2) true swamp species, and (3) ground species. Tlie 

 first group may be divided into two subdivisions : (a) those 

 growing on fallen mossy trunks, about tlie bases of living 

 gum trees, on dead cypress knees, bent gum roots, and on 

 decaying stumps ; (b) those growing exclusively on trunks and 

 branches of living trees. The first subdivision (o) comprises 

 the following species : Dnjoj)teris ma7'ginaJis, D. spimdosa, D. 

 gokUeann celsa, Polystichv/ni acrostlchoides, Aspleniam pldlyneuron, 

 Stnithopteris regdlis, S. clnnamomen, Botrychhim obliquam. The 

 second subdivision (h) contains but one species, Polypodiuvi poly- 

 podioides, which grows exclusively on the trunks and larger 

 brandies of living trees, usually high u^) in the tops, and prob- 

 ably on all the species of deciduous trees. The true swamp 

 ferns include but two species, ]Voodwardia virgiaica and TF. ureo- 

 l(U(i, which grow on the peaty remains of former vegetable life, 

 always in wet places and often, especially the former, in v^^ater. 



The ground ferns occur, not in the true peaty swamp, but in 

 the surrounding low sandy area, which nevertheless constitutes 

 a very large jjortion of the Dismal Swamp. These are Dryopteris 

 nnvehi)rar,ea8ls,D. thelypterls, Asplenium filixfcemi iia, Pteris aquilina, 

 Onocled sensihilis, Str'iithopleri^ regalis, S. clnnnmomed. But one 

 fern ally (SelagiaeWi apus) has l)een found. 



A study of many forms of the life of this vast swamp reveals 

 the interesting fact of the occurrence in abundance of many 



K;— Bior.. Sue. Wash., Vni.. XIH, ls!);i (dl) 



