CHAPTER IX 
LEAVES 
141. The Elm Leaf. — Sketch the leafy twig of elm that is sup- 
plied to you.! 
Report on the following points : 
(a) How many rows of leaves? 
(6) How much overlapping of leaves when the twig is held with 
the upper sides of the leaves toward you? Can you suggest a reason 
for this? Are the spaces between the edges of the leaves large or 
small compared with the leaves themselves ? 
Pull off a single leaf and make a very careful sketch of its under 
surface, about natural size. Label the broad expanded part the blade, 
and the stalk by which it is attached to the twig, leafstalk or petiole. 
Study the outline of the leaf and answer these questions : 
(a) What is the shape of the leaf taken as a whole? (See Fig. 
88.) Is the leaf bilaterally symmetrical, i.e., is there a middle line 
running through it lengthwise, along which it could be so folded 
that the two sides would precisely coincide ? 
(6) What is the shape of the tip of the leaf? (See Fig. 89.) 
(c) Shape of the base of the leaf? (See Fig. 90.) 
(d) Outline of the margin of the leaf? (See Fig. 93.) 
Notice that the leaf is traversed lengthwise by a strong midrib 
and that many so-called veins run from this to the margin, Are- 
1 Any elm will answer the purpose. Young strong shoots which extend 
horizontally are best, since in these leaves are most fully developed and their 
distribution along the twig appears most clearly. Other good kinds of leaves 
with which to begin the study, if elm leaves are not available, are those of 
beech, oak, willow, peach, cherry, apple. Most of the statements and direc- 
tions above given would apply to any of the leaves just enumerated. If this 
chapter is reached too early in the season to admit of suitable material being 
procured for the study of leaf arrangement, that topic may be omitted until 
the leaves of forest trees have sufficiently matured. 
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