13* A PINE. 



2. Needle-leaves. Observe: 



a. How the weak bases of each pair of leaves are enclosed 

 and stiffened by a sheath of scale-leaves. 



b. The toughness of the mature needles. Remove a pair, 

 pull away the scale-leaves, and observe: 



c. The dwarf branch on which the needles are borne. 



d. Draw a pair of leaves upon the branch that bears them. 

 IV. THE CONES. 



1. Staminate cones. Remove from the cluster one cone, note 

 and make sketches showing the outward appearance, the 

 arrangement of the sporophylls that compose it, and a 

 single microsporophyll, showing top and edge views. 



2. Carpellate cones. 



a. Young cone. By use of material collected about 

 June ist, observe the young cones emerging as lateral 

 branches at the tip of the young growth of shoot and 

 needle-leaves. The separate sporophylls are not con- 

 spicuous, but may be distinguished easily. Sketch. 



b. One-year-old cone. On some one-year-old shoots may 

 be seen cones that have grown considerably and that 

 have changed greatly from the appearance of the very 

 young cones. 



c. Two-year-old cones. Observe: 



i. The outer appearance and arrangement of mega- 



sporophylls or carpels. 1 

 ii. The completely sealed condition of old cones that 



were collected early in the spring, 

 iii. Draw. 



Remove some of the sporophylls, and observe: 

 iv. The general form. 



v. The seeds, and seed-wings borne upon them, 

 vi. Draw. 



1 For full statement regarding the structure of the carpel, see Coulter 

 and Chamberlain's "Seed Plants," Vol. i (Gymnospenms), pp. 69-77. 



