292 
THE LEAF 
On a sunny day set a stick parallel with the tip of a ragweed or other 
tall, slender weed. Set another stick about noon and another about 
three o’clock. Draw a diagram, or use your camera to show the changes 
in the position of the tip of 
the plant. Observe leaves of 
clover, and young daisy blos¬ 
soms. Do they change their 
positions with the sun ? What 
other plants do this? Does 
the age of the plant make any 
difference with its ability to 
change position? 
Bend a grass stem and 
fasten it flat. After a day 
or two observe its position. 
What changes have taken 
place? Remove the clasping 
leaf base and see what part of 
the stem was able to bend. 
Write notes telling what 
you have been able to observe 
in the cases above, and in any 
others which you may have 
noticed without being directed 
to do so. 
257. Economic Uses of 
Leaves. — The leaves of 
all the grasses as well as 
their stalks are used as 
food for cattle. Man uses 
for food the leaves of cab¬ 
bage, lettuce, spinach, 
celery, parsley, kale, kohl¬ 
rabi, and Swiss chard; 
and as a beverage, the 
leaves of the tea plant. The leaves of sofne of the mints, 
spearmint, wintergreen, peppermint, and sage, are used 
for flavoring, and the leaves of some plants, mullein, bone- 
Figure 270. — Pea Plant. 
The leaves are modified into tendrils for 
climbing. 
