A VEX A SATIVA. 187 



d. Draw various sections of stomata, with adjoining 

 cells of the epidermis. 



e. The modified large epidermal cells in the depres- 

 sions on the upper surface, the hygroscopic cells. 

 Draw. 



/. The modified epidermal cells at the summit of each 

 ridge; sometimes teeth may be seen. Draw. 



2. The hypoderma. Note its position and the character 

 of the cells. 



3. The mesophyll, all the chlorophyll-bearing part of the 

 leaf. Note 



a. The slight elongation of those cells next the epi- 

 dermis, forming palisade parenchyma. 



b. The large intercellular space under each stoma, and 

 the numerous smaller ones in other places. 



c. The abundant chlorophyll bodies. 



4. The fundamental tissue ; often reduced to only one 

 row of large empty cells surrounding the bundles. 



5. ^\^ fibro-vascular bundles ; compare those forming the 

 midrib and main veins of the leaf with those studied in 

 the stem. Compare with these the bundles of the 

 smaller veins, noting what tissues are absent from 

 them. 



6. Draw a portion of the section, including a large fibro- 

 vascular bundle, and some cells of the mesophyll and 

 fundamental tissue. 



7. Make a diagram of the leaf section to show relative 

 position and size of the different parts. 



Strip off two pieces of the epidermis. Mount one piece 

 with the outer surface uppermost, and the other with the 

 inner surface uppermost. Note 



