SURFACE 



143 



Surface. The surface is smooth when there are no out- 

 growths; spiny when there are spines; channeled when the 



FIG. 83 Barks. 1, Smooth bark, beech (Fagus grandifolia} ; 2, rough bark, 

 butternut (Juglans cinerea) ; scaly bark, red cedar (Juniperus virginiana) . 



