DIRECTIONS FOR LABORATORY STUDY. 383 



5. That the young sporophyte is fastened to the under side of 

 the gametophyte. (U 72, figs. 76-78.) 

 II. The sporophyte. 

 Taking the underground parts in a dish of water, observe 



1. The slender wire-like roots. How are they branched ? (^[ 91 

 ff.) Where are they attached to the stem? Trace an unbroken 

 one to the tip. The following points can only be seen on roots 

 carefully gathered and cleaned. What difference of color near 

 tip? Can you find many fine tangled root hairs? Where present ? 

 Where absent? (H 79.) 



2. Demonstration. Cut a longitudinal median section of a root 

 tip and show the tetrahedral (triangulai in section) apical cell ; 

 the segments cut off from inner faces producing root tissues, 

 those from outer face producing the root-cap. (U 77, fig. S3.) 



Cut a transverse section of an old root, mount and observe 



3. The outer brown mechanical tissues (also used for storage). 

 (H85.) 



4. The central whitish tissue, chiefly the stele, in which the 

 visible openings are the larger vessels. (If 81.) 



5. In what position does the stem naturally stand ? Observe 

 its occasional branching H[ 103) ; the surface covered with chaffy 

 scales (![ 128) ; the growing apex and dying base. 



6. Its nodes and internodes ; the nodes are indicated by the 

 attachment of a single leaf at each ; the internodes are the inter- 

 vals between the nodes. How are the leaves placed? (^[ 119.) 



Cut a transverse section of the stem and observe 



7. The outer brown mechanical tissues (also used for storage). 



(IT 129.) 



8. The circular, oval, or C-shaped white tissues, most of which 

 belong to the stele. Trace the course of the stele through at least 

 two internodes by cutting a series of rather thick (1 mm.) sec- 

 tions, observing the mode in which the stele branches to pass out 

 into a leaf. Cut also a longitudinal section through the base of 

 a leaf stalk and trace course of stele. (H1[ 130, 131.) 



Taking a perfect leaf, dried under pressure, observe 



9. The stalk or petiole, with its branches. Note the mode of 

 branching; the petiole divides into two equal'divergent branches ; 

 each of these forks, one branch carrying leaflets while the other 

 again forks, and so on. (^[1[ 153, 155.) 



10. The hardness of the mechanical tissues at surface of polished 

 petiole. 



