3-2 



LETTERS ON TREES, 



the vertical plants alone are figured — the side plants, 

 composing the branches, being supposed not to have 

 grown during the first few years.* 



4. In the centre of the trunk, just above the surface 

 of the ground, as figured on the plan, is an oblong 

 narrow clear space, bounded on every side by a dark 

 line of corresponding form, and terminating above in a 

 sort of head or tubercle. Directly above this is another 

 similar space, bounded by a similar line, and furnished 

 with a head or tubercle. And above this again is 

 another space exactly resembling the other two, and 

 enclosed after the like fashion. These lines, spaces, 

 and tubercles, represent respectively a section of the 

 woody stems, the medullary (pith) cavities, and the 

 buds of the first three in the series of fir-plants. From 

 the bottom of the first and undermost, is seen passing 

 down into the soil a single dark line : this is the root 

 of the first year's plant. From the bottom of the 

 second are seen two narrow lines, one on either side, 

 also j)assing downwards, — first along the stem, and 

 then along the root of the former, — at the extreme 

 point of which (below) they meet, and beyond which, 

 after meeting, they extend a short way as a single 

 line : These denote the root of the second year's plant. 

 And so of the third, — the roots of the third year's 

 plant passing down alongside first the stem and then 

 the root of the second year's plant, meeting at the tip 



* Compare this "plan" with figure 1 (A and B). 



