202 TRILLIUM. 



iv. Colorless parenchyma. 



v. The darkened (in fresh specimens green) mes- 



ophyll. 



Mount a portion of the epidermis stripped from the upper 

 surface of the leaf, and beside it a portion from the under 

 surface. Note 



g. The numerous dots in that from the lower surface, 



the stomata. 



h. The absence of stomata in that from the upper 

 surface. 



F. THE FLOWER. Note 



1. The several parts arranged in whorls. 



a. The outer whorl of three sepals, constituting the 

 calyx. 



b. The second whorl of three petals, constituting the 

 corolla. 



c. The third and fourth whorls of three stamens each, 

 constituting the androecium, 



d. The innermost whorl of three partly united carpels, 

 constituting the gynoscium. 



2. That the parts of the flower arise from the broadened 

 extremity of the stem, the receptacle. 



3. The alternation of the parts of each whorl with those of 

 the whorl next to it. 



4. The sepals. 



a. The shape. 



b. The color in a fresh specimen. 



c. The venation. 



d. Draw a single sepal. 



5. The petals. 



