294 THE PLANT COVERING OF OCRACOKE ISLAND. 



Myrica carolinensis Mill.^ 



Leaf bifacial, thickisli, botli surfaces sprinkled with resiniferous 

 glands, appearing to the unaided eye as granules of resin. 



Epidermis: Ventral, cells small, radial walls not undulate ; cuticle 

 thick, smooth; stomata none; long, pointed, unicellular hairs with 

 thick- walled, smooth cuticle scattered along the veins; short-stalked, 

 suj^erficially flat, scale-like, pluricellular glands occupying deep 

 depressions but usually rising above the level of the epidermis, these 

 filled with a mass of bright-yellow resin which breaks down the cell 

 walls and finally itself disorganizes, the stalk of each gland radially 

 surrounded by numerous small foot cells. Dorsal similar, but cuticle 

 less thickened, glands less numerous, and stomata present, lying in 

 all directions, each surrounded by 5 to 7 ordinary epidermis cells, the 

 guard cells slightly prominent. 



Chlorencliyma sharply differentiated into one very compact layer 

 of i)alisade with high, narrow cells, and several layers of open pneu- 

 matic tissue with rather large intercellular spaces. 



Colorless thin-walled parenchyma in narrow plates interrupting the 

 chlorenchyma above and below the smaller vein^. 



Hypodermal collenchymatic tissue, thick-walled, in 2 or 3 layers 

 above and below the midvein. 



Mestome bundles of midvein reinforced by stereome which adjoins 

 both the hadrome and the leptome, that below the leptome separated 

 from the hypodermal collenchymatic tissue by a little thin-walled 

 parenchyma. 



Myrica cerifera L. 



Leaf usuall}^ somewhat thinner than in M. carolinensis. 

 Epidermis similar, but with fewer hairs along the veins. 

 Palisade somewhat thicker, in 2 layers of lower cells. 



QUERCUS VIRGINIANA L.^ 



Leaf persistent, thick, bifacial, upper surface shining, margins 

 sometimes revolute, veins, especially the midvein, prominent beneath. 



Epidermis: Ventral with nonundulate cell walls, the outer, espe- 

 cially , strongly thickened ; cuticle thick, smooth; stomata none; hairs 

 none. Dorsal, cell walls as on the ventral surface ; stomata with guard 

 cells slightly i)rominent, lying in all directions, each bordered by sev- 

 eral small epidermis cells; hairs (fig. 43) forming a dense covering, 

 stellate, consisting of 8 to 18 acute, thick-walled unicellular arms 

 upon very narrow foot cells, cohering toward their bases so as to form 

 a saucer-shaped scale. 



^ Material examined from near Norfolk, Va. 



^Q. virens Ait. Material examined was from near Norfolk, Va. Compare 

 Quercus ilex as described and figured by Lalanne, Recherches, p. 3, pL 7, ff. 9, ii. 



