104 ANATOMY OF STEMS, ROOTS, AND LEAVES 



3. Examine a small piece of algse that has been kept in alcohol and 

 stained with eosin. Note the protoplasm and nucleus. 



4. Examine a very thin section of potato under the microscope and 

 note the starch grains. Stain with dilute iodine and examine again. 



5. Cut a very thin crossi-section from the pith of corn stalk. Note 

 the parenchyma cells and the fibro-vascular bundles. Study out the parts 

 as indicated in the figures. 



l>. Geranium Stem. — Cut a very thin cross-section of the stem of a 

 geranium. Note tlie parts as indicated in Figs. G7, 70. 



7. Woody Stem.- — Cut a very thin cross-section of a twig from a 

 tree. Note tlie, ])artii as indicated in Fig. 74. 



8. Many Forms of Cells.— Make longitudinal sections of all of the 

 above stems and find as many kinds of cells as possible. 



!•• Leaf Structure. — Hold a bit of a leaf between two pieces of pith 

 and cut very thin cross-sections. Examine under the miscroscope and note 

 tlie parts as indicated in Fig. 77. 



10. Peel small fragments of epidermis from both lower and upper 

 surfaces of a leaf and examine under the microscope. 



11. Root Structure. — Hold a young root from corn or bean between 

 two pieces of pith and cut very thin cross-sections. Examine under the 

 microscope and note the i^arts as indicated in Figs. 75 and 76. 



QUESTIONS 



L Wliat do you understand by fibro-vascular bundles? 



2. How are tliey arranged in the plant? 



3. What do you understand by plant cell? 



4. What are some of the difl'erent kinds of plant cells? 



5. What do you understand by protoplasm? 



6. What else do you find in plant cells? 



7. Wliat is the cambium? Where is it located? 



8. Explain the difference between mono- and dicotyledonous stems. 



9. What is meant by phloem and xylem? Where are they located? 



10. What are the medullary rays? , 



11. What are annular rays? 



12'. What is meant by epidermis? 



13. In what parts of the plant do you find chlorophyll? 



14. What is meant by mesophyll ? 



15. What and where are the trichomes? 



