EXERCISE 6 

 BY WHAT ROUTE DOES WATER REACH THE LEAVES? 



Materials. Leafy branches of tree or shrub, preferably at least 

 one-half inch thick at base ; soft leafy stems, such as geranium, 

 coleus, celery, or almost any common weed or herbaceous flowering 

 plant, but semitransparent stems, as yellow coleus, are best; eosin 

 or red ink. 



Directions for work. Color some water with eosin or with 

 red ink. Stand freshly cut stems with lower ends in the 

 colored water. Place the experiment in a sunny place for 

 later examination. 



1. Woody stems. When the branches have been standing in 

 the colored water for some hours, remove them from the solu- 

 tion and cut sections at various heights along the stems. Also 

 split the pieces lengthwise. Trace the path of the water into 

 the branches and, if possible, to the leaves. 



Does the water travel in the pith, the wood, or the bark ? 

 (See textbook for definition of terms.) What can you learn 

 about the distribution of water throughout the leaves? 



2. Herbaceous stems. From twenty minutes to an hour is suf- 

 ficient to secure results with such stems as geranium or coleus. 



Section and examine in the same way as directed for woody 

 stems. Note carefully the path of the water. 



References 



BERGEN and CALDWELL. Practical Botany, p. 11. 



BERGEN and CALDWELL. Introduction to Botany, pp. 12, 13. 



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