PROBLEM 77 



93 



Conclusion. — 1. Ju(lj2;c(l from the texture, what iiiij!;lit be the 

 use to the plant of the outer layer of the l)ai-k ? 



2. Judged from the color, what might l)e the use of the middle 

 layer ? * 



NOTE. — The inner layer of bark is known as the hast. It consists of tuliclike 

 cells which carry food from the leaves toward the roots. 



3. What are all the uses of the bark? 



Drawing. — Make a cross section of a woody stem, labeling all 

 the parts. 



Home Work. — Take two potatoes of equal weight. Peel one, 

 leave the other unpeeled. Place the peeled potato (with peelings) 

 on one pan of a balance, the unpeeled potato on the other. Allow 

 these to remain on the balance for several days. What changes 

 do you note? Remembering that the potato is an underground 

 stem, determine another function of the bark. (See page 99, 

 Civic Biology.) 



Problem 77 : To prove that 

 liquids rise through stems. 

 (Review.) 



Materials. — Growing pea or 

 bean seedling, red ink. 



Method. — Place the roots 

 of a growing plant in a weak 

 solution of eosin or red ink. 

 Leave a few hours in a sunny 

 place. 



Observations. — Notice the 

 stems and leaves of the young 

 plants, particularly the veins in 

 the leaves. Copy the accom- 

 panying figures in your note- 

 book and color them to show 

 where fluids rise. 



Conclusion. — Through what 

 part of the stem and leaves 

 uo liquids rise? 



