74 COMMON LI VER WOR T. 



ii. Chlorophyll-bearing filaments ; springing indif- 

 ferently from the floor or walls, 

 iii. The (usually single) layer of small cells form- 

 ing the floor, partition walls, and roof of the 

 cavities. 



iv. The stomata, these will occasionally be cut 

 across ; note the number of cells in depth, 

 and their relative size. 

 v. Make a drawing to illustrate the several 



points. 



Make a longitudinal antero-posterior section and note 

 g. The length of the parenchyma cells, and shape of 



the air cavities. 



h. Remove a thin paring from the flat posterior 

 surface of the pedicel, and mount with the free 

 surface uppermost, noticing the epidermal cells and 

 stomata. Draw. 



i. Remount the section with the free surface down- 

 ward ; note the relative size of the air cavities, 

 and the appearance of the stomata. 



Cut off a pedicel near the base, make an antero-posterior 

 longitudinal section of the basal portion, together with the 

 stem from which it arises, and note 



j. The continuity of the tissues of the pedicel with 



those of the stem. 



Cut off a pedicel near the head, make an antero-posterior 

 longitudinal section passing through the pedicel and through 

 the cleft in the receptacle, and note 



k. The continuity of the tissues of the pedicel with 



those of the receptacle. 



2. The receptacle ; cut a transverse section of one of 

 the rays, and notice 



a. The central cavity in which lie numerous hairs 

 like those in the grooves of the pedicel. 



