THE STUDY OF TREES. 257 



We need not at this stage follow the section further in 

 detail. If a similar twig is peeled in the spring in the way 

 we have done, it will be found to be somewhat wet and 

 sticky just against the wood. There is much sap here at 

 this time, because this is the region where growth in thick- 

 ness is going on, and although we cannot see it, this is the 

 layer known as the Cambium. Just next to it on the out- 

 side (the dark ridge we noticed in our first section of the 

 twig) is the region known as the Bast, down which the 

 elaborated food passes from the leaves. The water 

 with mineral salts in solution passes up the later made 

 wood. 



There are other things to be seen in a section of a twig, 

 but we may leave these undescribed at present. 



The foregoing points having been noted on a twig, others 

 of different trees should be gone over and similar observa- 

 tions made. Pupils should also write down the distinctive 

 characteristics of each. The following should be included 

 in the description of a twig. 



Season examined : 



General habit of twig, i.e. diameter ; slender, stout, 

 straight, angled, smooth, rough, or downy ; colour ; 

 odour, if any ; etc. 



Markings on bark, i.e. lenticels, longitudinal or trans- 

 verse, large, small; leaf scars, size, shape, arrange- 

 ment (opposite, alternate, close, far apart) ; ring scars, 

 distance apart ; etc. 



Buds. Size, shape, colour, and any other distinctive 

 feature. 



N.S. 17 



