DESCRIPTION 41 
have the same number of leaflets? Are the leaves pin- 
nately or palmately compound? Can you work out any 
relation between these two classes of leaves in this 
study? Illustrate by means of outline drawings. Re- 
port your results and conclusions to the instructor. 
Study several horse-radish plants and note that they 
bear both simple and compound leaves. Where do you 
find the compound leaves? Is there any advantage in 
having them thus situated? 
Does your study of leaves thus far seem to indicate 
any relation between leaves of various forms? 
Cut a maple twig bearing several leaves from a 
well shaded portion of atree. Are the leaves opposite or 
aternate? Are the petioles of the same age equal in 
length? Do they all form equal angles with the stem? 
How do these variations affect the light relations of the 
leaves? Throw the twig bottom-side up on the table so 
that the leaves will have nearly the same relative position 
they had while on the tree. Make an outline drawing of 
the terminal end of the twig, including six leaves (x4). 
In accordance with the above outline study a beech 
twig and make a drawing similar to the one made of 
the maple twig. Study and describe the light relations 
of the leaves of the following plants: lilac, horse-chest- 
nut, milkweed, and prickly lettuce. 
Leaf Movements. 
Exp. 25: On a bright, clear day note the position of 
the leaflets of the compound leaves on a locust tree and 
a clover or Oxalis plant, about 6 A. M.,9 A. M., 12 M., 
3 P. M., and 8 P. M. By means of diagrams represent 
