A MANUAL OF BOTANY 31 



12. Physiology of Ste:ms 



(Some of the experiments can be made by the stiulcnts, others will 

 have to be demonstrations by tlie instructor. ) 



Exp. 1. The water content of various woods. (Students.) 



Weigh blocks of different woods freshly cut and after 

 drying. 



Exp. 2. Water content of heart and sap woods from 

 freshly cut trees. (Students.) Conduct experiment as in 1. 



Exp. 3. Eapidity of decay ; durability. (Students.) 



Keep blocks of wood in moist warm earth for one month. 

 Examine for signs of decay. 



Exp. 4. Amount of ash. (Students.) 



Weigh, burn, and weigh the ash remaining. 



Exp. 5. Path of upward sap movement. (Students.) 



Place fresh cut elder, lilac, or other twig in eosine solution 

 for 24 hours. Make long sections through pith, wood, and 

 bark, and observe region of discoloration. 



Exp. 6. Path of the downward movement of elaborated 

 sap or food in solution. (Instructor.) 



Exp. 7. Tensile strength. (Students.) 



Weights square rods of equal area and length will sup- 

 port before breaking. 



Exp. 8. The "bleeding" of woody plants, particularly 

 maples, grapes, hickory, and birch, in early spring. (Students.) 



Exp. 9. Effect of light and direction of exposure on the 

 color and thickness of bark. (Students.) 



Vujve holes in the different sides of trees for thickness. 



Exp. 10. Earthpull or geotropism. (Students.) 



Observe the direction of leafy stems, branches, runners. 



Exp. 11. Lightpull or heliotropism. (Students.) 



'As in 10. 



Exp. 12. The epidermis coating or protective "varnish." 



(Instructor.) 



Exp. 13. Food storage of stems. (Instructor.) 



