48 STUDY OF COMMON PLANTS. 



Draw an outline sketch, locating the position of the me- 

 chanical elements. 



III. Cut through an old tendril of a grape-vine. Notice 

 the disposition of the wood elements. Test its strength. 



IV. Study under the compound microscope the bast 

 fibers of basswood and other common plants. 



V. Write a brief account of what you have ascertained 

 regarding the mechanical arrangements for the support of 

 the plant. Read Goodale, Physiological Botany, pp. 188- 

 194 ; Haberlandt, Physiologische Pflanzenanatomie, p. 96 

 et seq. 



Transportation of Food in Solution. 



I. Cut a short branch from a grape-vine. Immerse the 

 cut end in a colored solution, such as red ink. After 

 some time make transverse sections, and observe how far 

 and through what parts of the stem the colored fluid has 

 penetrated. 1 



II. Repeat the experiment, using a fresh leafy stem of 

 Tradescantia for the purpose. Place finely powdered 

 indigo in the water and allow the plant to be exposed to 

 sunlight. This time take the precaution to cut the stem 

 under water so as to prevent the entrance of air. If the 

 cut is made slanting, and the whole operation skillfully 

 performed, the particles of indigo can be seen under the 

 compound microscope as they enter the vessels of the 

 Tradescantia. 



Storage of Food. 



I. Cut a common potato in two. Make thin sections 

 from the exposed surface, and examine with the compound 



1 On the ascent of water in woody plants, see H. Marshall Ward, Tim- 

 ber and Some of its Diseases, Chap. IV (Nature Series). 



