PLATE LXVII. 



Fig. 8. An oblique section of a leaf nearly parallel to the surface and 

 embracing zones from surface to surface. Stained with methylene blue. 

 Stippling indicates cells whose contents were deeply stained : g, upper 

 epidermis; h, palisade cells; k, border parenchyma; t, tracheid with an- 

 nular thickenings; j, lower epidermis; r, stoma. X 187. 



