486 



BOTANICAL SURVEY OF DISMAL SWAMP REGION. 



Hypodermal collenrhy mafic tissue beneath the larger veins. 

 Stereome surrounding the inestome bundles, especially strong above 

 and below them. 



Smilax laurifolia L. 



Hygrophile Forest formation. 



Leaf thick, evergreen, strongly bifacial, markedly xerophytic in 

 structure (tig. 86). 



Epidermis; Ventral, cell walls thiekish, the radial strongly undulate; 

 cuticle thick, finely wrinkled, yellow, sharply differentiated from the 



St. r-, 



Pig. 86.— Smilax laurifolia, leaf in cross section. «, Ventral face; i>. dorsal face. Magnified 300 



times. 



whitish, highly refractive outer walls of the epidermis cells. Dorsal, 

 radial walls not undulate; cuticle thicker than on the ventral surface, 

 nearly equaling the height of the lumina of the epidermis cells, 

 strongly wrinkled, with a few broad, blunt ridges to each cell, other- 

 wise as on the ventral surface. Stomata only on the dorsal surface, 

 lying at right angles to the leaf's axis, deeply sunken (below the 

 cuticle). Hairs none. 



Palisade in two dense layers, the cells wide, with thick, pitted walls; 

 then several layers of short-celled pneumatic tissue, with rather large 

 intercellular spaces; and finally, beneath the dorsal epidermis, two 

 rather compact layers of short cells. 



