THE LEAF. 33 



The stipules of the Tulip-tree serve as bud-scales, falling off 

 soon after the leaves unfold. In some plants, as the Dock, the 

 Buckwheat, etc., they unite and form a sheath around the 

 stem. The sheath of the Grasses represents the petiole, for it 

 bears the blade at its summit ; the small appendage com- 

 monly found at the top of the sheath, called a lignile (Fig. 

 47), is of the nature of a stipule. 



Specimens should be collected to illustrate all the points mentioned in the 

 chapter, and figured, as suggested above. Illustrative specimens for preserv- 

 ation should be pressed till dry, and then mounted on cardboard or heavy 

 white paper. They can be attached by means of liquid glue, or by using 

 strips of gummed paper or white court plaster. Opposite or below each 

 the points illustrated should be indicated by the appropriate term. 

 3 



