41 6 BOTANICAL SURVEY OF DISMAL SWAMP REGION. 



to fire were observed in the Dismal Swamp region. 1 Forest? lires are 

 here sometimes accidental, but are often purposely started in order to 

 produce in the following spring a more extensive development of 

 young shoots of the cane (Arundinaria), which are eagerly grazed 

 by cattle. The tendency of these fin's is to destroy the older timber 

 (especially the pines), and thereby effect a more vigorous shrubby 

 growth. Certain herbaceous plants, notably the fireweed {ErecMiles 

 hieracifolia) and other Compositae, multiply rapidly upon land that 

 has been ravaged by fire. 



CLASSIFICATION OF LIANAS. 



As nearly all the lianas, or climbing plants, both xerophilous and hygrophilous, 

 which occur in the Dismal Swamp region are represented in the mixed forest 

 formation of the Wooded Plain, there can be no better place than this for an 

 enumeration of the species that possess this life form, so conspicuous and impor- 

 tant in the region. The lianas may be classified '-' according to their mode of 

 climbing, as follows: :: 



1, Clambering without development of local sensitiveness and not twining 

 (Kletterpflanzen); in our two plants by means of hooked prickles: 



* Polygonum arifolium. * P. nagittatum. 



2. Climbing by negatively heliotropic aerial roots: 



Decumaria barbara. Tecoma radicans. 



Rhus radicans. 



8. Twining: 



*Dio8Corea rillom. * Strophosiyles helvola. 



*Clitoria mariana. Berchemia scandens (volvbilis) . 



* Bradburya (Centrosema) Virginia ita. (lelsemium sciuju'rvircns. 



*(!atactia volubilis. * Vincetoxicum (Oonolobus) carolinen- 

 * Falcata comosa {Amphiearpaea tuo- sis, 



noica), Lonicera sempervirens. 



* Apios apios (tuberosa), * Willughbaeya {Mikania) scandens. 



* lihi/nchosia tmnentom. 



4. Climbing by tendrils, consisting of: 

 (a) Modified leaves — 

 Smilax app^ (metamorphosed stipules). Th'gnnma crucigera (metamorphosed 

 Clematis crispa (metamorphosed peti- leaflets, ending in adhesive thicken- 

 oles). ings). 



(/>) Modified shoots — 

 Vitis spp. *Melothria pendula. 



Parthrnocissiis (Atajtclopsis) (pdnque- Ainpelopsis arborea (Cissus stans). 

 folia. h 



1 Warming (Lagoa Santa, 2r>0 to 2(515 and 466 to 469) descries the devastating fires 

 to which the vegetation of the Brazilian ' ' Campos " is exposed, and mentions certain 

 important changes in the plant life of that region winch be believes to have been 

 brought about through the long-continued operation of this factor. 



-The classification is that of Schenck, Beitriige znr Biologie nnd Anatomie der 

 Lianen, I Theil, Biologie pp. r> to 8, (1892). 



:i The names of herbaceous species are marked with an asterisk. 



4 Also mostly provided with booked prickles. 

 Tendrils ending in adhesive disks. 



