210 TRILLIUM. 



c. The several tissues of the bundle. 



i. The phloem, of long, thin-walled, uniform 



cells. Draw, 

 ii. The vessels, of various sizes and kinds. Draw 



some of each. 



iii. The wood parenchyma, considerably like the bast 

 parenchyma, but in its best development with 

 thicker walls, and more evident somewhat 

 oblique end walls. Draw. 



Strip some epidermis from the surface of the stem, and 

 under low power, notice 



10. The shape and arrangement of the cells, and of the 

 stomata. Draw. 



D. THE LEAF. Make a vertical section near the middle 

 of a foliage leaf, at right angles to the principal veins, and 

 notice 



1. The row of colorless epidermal cells bounding the upper 

 and lower surfaces. 



2. Here and there transverse sections of the veins. Note 

 the depression above, and the convexity below the 

 larger veins. 



3. The mesophyll. Note 



a. The layer of closely set cells along the upper side, 

 palisade parenchyma. 



b. The loose irregular tissue on the lower side, spongy 

 parenchyma. 



Under high power, notice 



c. The shape and position of the cells of the palisade 

 parenchyma. 



d. The shape of the cells of the spongy parenchyma 

 and the numerous intercellular spaces. 



e. Contents of the mesophyll cells. 



