30 COLLEGE BOTANY 



herbaceous shoot. Note the large, thin-walled, isodiametric, overlapping 

 cells and the intercellular spaces. Test for cellulose (page 145). 



Exercise 2. Examine thin sections of potato tuber, apple and fleshy- 

 roots and note the same points as in Exercise 1. 



Exercise 3. Examine a thin cross section of a leaf. It is composed 

 almost entirely of parenchyma tissue. 



Exercise 4. GoUenchyma tissue. Examine thin sections of Begonia 

 stems and locate the cells with thick walls, especially at the angles. 



Exercise 5. Sclerenchyma tissue. Examine sections made from Dahlia 

 root and note the thick-walled cells. Also note the canals running through 

 the walls. 



Exercise 6. Examine sections of the shells of any nuts that may be con- 

 venient and note size and character of the cells. 



Exercise 7. Fibrous tissue. Examine thin longitudinal section of the 

 wood of Basswood {Tilia americana) which have been macerated by heat- 

 ing in a test tube, in nitric acid with a little potassium chlorate. Tease the 

 cells apart with needles. Note shape and arrangement of the cells. 



Exercise 8. Do the same with the inner bark and note the bast cells. 

 Compare with wood fibers. ' 



Exercise 9. Tracheary cells. Examine longitudinal sections of the 

 corn stem and note the different kinds of tracheary cells. 



Exercise 10. Tracheids. Examine radial sections of pine wood and note 

 the tracheid cells. 



Exercise 11. Sieve tissue. Examine longitudinal sections of pumpkin 

 vine that have been preserved in 99 per cent, alcohol. Note the sieve tissue. 



Exercise 12. Laticiferous tissue. Examine longitudinal sections made 

 from the inner bark of the milkweed or spurge. Note the laticifer- 

 ous tissue. 



