10 LABORATORY AND FIELD EXERCISES 



Draw a few branches with leaves on the upper, 

 middle, and lower portions of the trunk. Indicate 

 the position of the remaining branches by circles or 



frogeotropic 

 taproot 



Dingeotropic roots 



FIG. 5. Pine trees illustrating the erect type 



a, a young pine ; 6, a mature pine. Observe the excurrent trunk, the false whorls 

 of branches, and the pyramidal form. Consult the text for the main factors con- 

 cerned in the seasonal growth (1-7) and the development of these external features 

 of the pine 



other symbols. Consult Fig. 5 above and the text 

 discussion on the form and development of the pine. 

 d. Summarize briefly the facts relating to bud and branch 

 growth which determine the erect pyramidal form 

 of the pines and spruces. 



