286 



THE PLANT COVERING OF OCRACOKE ISLAND. 



slit-like furrows between each 2 nerves (hence 2 to every ventral 

 furrow), opening into wider air spaces with stomata at each side of 



the bottom. Stomata also oc- 

 cur near the bottom of the ven- 

 tral furrows, but are there less 

 numerous. 



Epidermis: Ventral (fig. 34) 

 with cell walls thinner than on 

 the dorsal surface, many of the 

 cells extended into straight or 

 curved, spreading, unicellular 

 hairs which line the main cav- 

 itj' and lateral furrows with 

 a dense cross work, and are 

 larger, thinner -walled, and 

 more slender than those which 

 occur on the dorsal surface; 

 bulliform cells none. Dorsal 

 (fig. 35) with smaller cells, the 

 outer Avail and cuticle so 

 greatl}^ thickened as nearly to 

 equal the cell lumen, the areas \ying above the subepidermal strands 

 of stereome having single rows of short cells which alternate with 

 several rows of long ones; many of the epidermal cells extended into 

 short, stout, pointed, thick-walled, unicellular, appressed, prickle- 

 like hairs, which line the furrows. 



Subepidermal stereome: None on the 

 ventral side of the leaf and in the margin; 



Fig 



-Muhlenbergia fil ipes—triLnsYerse section of 

 leaf. Scale 75. 



'Fig. ^.—MuhJenbergia fiUpes— 

 ventral epidermis of leaf. 

 Transverse section, showing 

 the hairs. Beneath the epi- 

 dermis are layers of colorless 

 parenchyma. Scale 400. 



Fig. 35.- Muhlenbergiafilipes— dorsal part 

 of leaf blade. Transverse section show- 

 ing the epidermis (Ep.), stereome (St.^^ 

 and rather thick- walled colorless paren- 

 chyma (Pa.), which borders on the 

 mestome bundle. Scale 400. 



on the dorsal side in the form of flattened supporting strands^ 

 beneath the mestome bundles, passing gradualh' into the often 



^" Abgeplattete Trager," Schwendener, Mechan. Princ, p. 40. 



