VIII. BUDS AND STEMS 



Structural Differences between the Stem and the Root. — Wash carefully 

 the earth from the roots of a pea seedling that you have grown in the 

 laboratory. Try to make out the following points: (1) note the differences 

 in color between the stem and roots; (2) compare the manner in which the 

 root and stem give off lateral branches. Notice that the leaves and lateral 

 branches from a stem are more or less regular in position, while the small 

 roots have no regular method of leaving the primary root. The places on 

 the stem where leaves are given off are known as nodes, the part of the 

 stem between being called an internode. 



In a growing stem of any woody plant, notice the end of the 

 stem ; the bud at the termination is a future stem. It is well for 

 us to remember that a stem is a developed bud, as we shall see 

 when we take up the work on the bud more in detail. 



One difference which is very noticeable between the stem and 

 the root is the color, the young root being whitish or gray, and 



the young stem being 

 green. The following ex- 

 periment will serv^e to 

 explain this difference: — 



Effect of Absence of Light 

 on Young Plants. — Plant 

 some peas in sawdust within 

 a box, or wide-mouthed bot- 

 tle which has been previously 

 blackened so that no light is 

 admitted to the interior. 

 Grow some of the same seed 

 in a box alongside the covered 

 material, giving each the same 

 amount of heat and moisture. 

 After the young plants have 

 grown, take one out, compare 



it with the ones grown in the light, and note the difference in color. 



Might the absence of light account for the color of the root? 



The seedlings which have been grown in darkness show some 

 other interesting conditions. The stems are long and more or 

 less reclining on the sawdust. The leaves are hardly worthy of 

 the name, being reduced to little scales. We know that they are 



98 



A pocket garden which has been kept in complete 

 darkness for several weeks. Notice the condition 

 of stems and leaves. 



