FIX US S YL VESTRIS. 135 



and then rapidly to a point, and bearing the 

 thick-set bases of the bud scales, in the axils 

 of which may be seen 



iii. Secondary buJs? Take out one of these buds 

 carefully and dissect it. Note the scales which 

 cover it. By cautiously removing these the 

 rudimentary nccdle-lcares, looking like two 

 minute knobs, may be found, apparently at 

 the end of a very short stem to which the 

 scales were attached. 



iv. Make drawings showing the external appear- 

 ance and structure of the buds, both main 

 and secondary. 

 d. Compare the buds with the branches. Observe 



that a bud is simply an undeveloped branch. 



5. The structure. Cut an old stem square across to study 

 the cut surface. Mount also a transverse section of 

 the same. Notice 



a. A central yellowish or brownish spot of irregular 

 outline, the pith. 



b. Surrounding the pith a zone of firm tissue, the 

 wood. Observe 



i. The concentric masses of tissue, growth rings, 

 the number depending upon the age of the 

 shoot at the point cut. In thin parts of the 

 section, notice the difference between the 

 central and peripheral portions of any growth 

 ring, 

 ii. The many fine radiating lines, the medullary 



rays. Note the extent of the larger ones, 

 iii. Many small scattered openings, the resin ducts. 



3 These can only be found of sufficient size to dissect in buds collected 

 late in autumn or in early spring just before they begin to expand. 



