*4 2 SCOTCH PINE. 



MINUTE ANATOMY. 



A. THE STEM. Cut a transverse section of a year-old 

 stem, examine with a low power and note 



1. The pith, occupying the center of the section. 

 Observe 



a. The outline of the pith. 



b. In some sections a portion extending outward to 

 enter a dwarf branch. The salient angles of the 

 pith are all due to such outward extensions at 

 different heights. 



c. The loose arrangement of its cells. 



2. The wood (xyleni). Observe 



a. The arrangement of the cells. 



b. The openings of the resin ducts. 



c. The division into two zones, growth rings. 



3. The cambium ; a narrow, cloudy looking zone, bound- 

 ing the xylem. (If the section be from a stem gathered 

 in winter or early spring, the cambium zone will be 

 indistinguishable.) 



4. ^^ phloem ; of compactly-arranged cells, with a whitish 

 appearance. 



5. The cortical parenchyma ; outside the phloem, consisting 

 of large, loosely-arranged cells, which in sections of a 

 fresh stem contain much chlorophyll. In this region 

 note the large oval openings of resin ducts. 



6. Dark lines from the pith to the cortical parenchyma, 

 the medullary rays. 



7. The edge of the section. The cortical parenchyma is 

 bounded by a row or two of small close-set cells. All 

 the tissue beyond this belongs to the bases of the scale 

 leaves, which cover the stem. 



