LIVEEWOET 313 



c. The "leaves." — ISTote also the sections of the 



" leaves " among the rhizoids. What is the struct- 

 ure of these bodies ? 

 Draw portions of your sections to show the structures 

 studied. 



Make longitudinal sections through the thallus and 

 compare them with the sections just studied. Draw. 



d. The stomata. — Select a flat thallus, lay a portion 



of it on a slide, and examine with a high power. 

 Note the distribution of the stomata. Select a 

 single well-formed stoma and study its structure. 

 What is the shape of the stoma ? Of how many 

 cells is its rim formed? What is their shape? 

 How are they arranged ? Do they contain chlo- 

 rophyll? Focus down into the cavity of the 

 stoma and note the guard cells, which project 

 into and partly close the opening of the stoma. 

 Examine the under surface of the thallus for 

 stomata. From the same or another flat thallus 

 make tangential sections, i. e., sections parallel to 

 the flat surface of the thallus, so as to remove 

 only the " epidermis." Examine these with the 

 high power and compare with the other prepara- 

 tions which show the structure of stomata. Parts 

 of the section will probably show the manner in 

 which the green cells lying immediately under 

 the " epidermis " are divided into groups. 

 Draw a sectional and a surface view of a stoma. 



e. The fruiting organs. 



1. The cupulas and gemm£e. — With a dissecting- 

 needle pick out of the cupules some of the gem- 

 mse, mount them in a drop of water, and ex- 

 amine under a low, then a high power. What 



