138 SCOTCH PINE. 



ii. The longitudinal rows of whitish dots on both 

 surfaces. Cut a thin slice from the convex 

 surface, mount, and examine by transmitted 

 light. If sufficiently thin, the dots will now 

 be seen to be minute openings, the stomata or 

 breathing pores. 4 



g. The structure. Cut a transverse section and 

 examine by transmitted light. Notice 

 i. Occupying the center an oval patch of whit- 

 ish tissue, the fibro-vascular region. 

 ii. Outside the central whitish area, compact 

 green tissue, mesophyll. In this zone notice a 

 dozen or more openings, the resin ducts. 

 iii. Enveloping the whole, the narrow colorless 



cortical area. 

 iv. Draw the section. 



Cut a longitudinal section parallel to the flat side. Make 

 out the same regions as in the transverse section. 



D. THE FLOWERS. 



i. Male or staminate. Carefully break off one of the 

 clusters. 



a. Note the short stalk by which it was attached to 

 the stem. 



b. Note that the cluster is made up of numerous 

 short-stalked bodies, the stamens, attached to an 

 axis. Each stamen consists of a flat scale bearing 

 on the inferior surface two enlargements, the 

 pollen sacs. 



c. Burst a pollen sac. Note the innumerable minute 

 grains of pollen which escape. 



4 More accurately, the external chambers of the stomata, for the real 

 stomata are deep seated. 



