224 PRACTICAL BOTANY. 



gards the outside and the center of the stem ? Where 

 are they most abundant ? The space between the bun- 

 dles is filled with thin-walled fundamental parenchyma. 

 Trace this towards the outside of the stem, and notice 

 that it changes near the epidermis into thick-walled scle- 

 renchyma. Notice the same change as you approach the 

 fibrovascular bundles. Is the epidermis regular or irreg- 

 ular ? Find places in the epidermis where the section has 

 passed through stomata ; notice the guard cells. In con- 

 nection with this observation, mount bits of the epidermis 

 torn from the stem with the forceps, and study the sur- 

 face view of the stomata. 



Find and identify in your section all the parts shown in 



Fig. 142. Draw a fibrovascular bundle and label the parts. 



5. Cut longitudinal sections through an internode, mount 



in Schultze's solution, and identify all the above tissues 



as seen in longitudinal sections. 

 Study the markings on the large 

 vessels. Trace some of the fibro- 

 vascular bundles as far as you can, 

 and state what you observe. 



6. Cut transverse and longitu- 

 dinal sections through a node of 

 the stem, mount in dilute caustic 

 potash, and trace the fibrovascular 

 bundles in their passage through 

 the node. Notice especially the in- 

 tercommunication of the bundles. 



7. Mount bits of the epidermis 

 torn from both the upper and the 



FIG. 143. Epidermal cells lower sides of the leaf. Do you 



and stomata of Corn. find stom ata on both sides ? Draw 



a stoma under high power with its two guard cells and 



two subsidiary cells. Are the stomata arranged in any 



definite way ? Note the shape of the stomata when 



