28 THE GROWTH AND PARTS OF PLANTS 
glass. Place it in a horizontal position. This may 
be done behind a. pane of glass in a box, or a pin may 
be thrust through the kernel into a cork which is 
then placed as in Fig. 51, with a hit- 
tle water in the bottom of the vessel 
to keep the air moist. 
In several hours, or on 
the following day y) ob- FIG. 52. Same maize seedling as shown 
serve the position of the in Fig. 51, twenty-four hours later. 
root. The greater part of it remains in a horizontal 
position, but the end of the root has turned straight 






downward again. 
What part of the root bends when it turns from the 
horizontal position? We should now determine what 
part of the root it is which bends when it grows down- 
ward in this fashion. To 
do this the root of another 
seedling should be marked 
and placed in a_ horizontal 
position. With a fine pen 
and India ink, mark spaces 
as close together as possible, 
about 1 mm. apart, begin- 

Fig. 53. Marrow seedling placed hori- 
zontally and marked to show where the ning at the tip of the r oot. 
root bends when turning downward. 
Mark off ten such spaces, as 
shown In Fig. 53, and leave the root in a horizontal 
position for a day. Now observe where the curve has 

