28 
LABORATORY EXERCISES 
EXERCISE 30 
LEAF ARRANGEMENT 
I. (Specimens may be studied in the field or may be brought 
into the laboratory.) Examine the branch of a maple tree. How 
many leaves do you find at each node? What is their arrangement 
with reference to each other? Examine the leaves of an apple 
tree. How does the arrangement differ from that of the maple 
leaves? (These are the more common forms of arrangement.) 
Find a plant in which three or more leaves appear at a single node. 
II. Observe the leaf arrangement of common shrubs, trees, and 
herbs. Tabulate as follows: 
Name op 
PLANT 
Arrangement 
Number of 
leaves at node 
Opposite, alternate, 
or whorled , 
III. Note the leaf arrangement in each of the plants observed 
which makes possible the exposure to sunlight of the largest extent 
of leaf surface. Note especially the ‘‘ rosette ” arrangement of 
the leaves of the dandelion and the common plantain. Note also 
some common vines such as the climbing roses, the ivy, the morn¬ 
ing glory, and the grape vine. 
IV. What is the function of a leaf? Of what advantage are 
the various arrangements of leaves? Why is it important that 
leaves be exposed to sunlight? 
