WORK OF THE ROOT 



47 



injured and its growth stopped, look for roots emerging 

 from the base of the stem. In a still older plant, note 

 what a large part of the soil is drained by the later branches 

 which grow in various directions. 



Growing-region of the stem. On seedlings still growing 

 in the pots carry out a similar experiment with the stem, 

 selecting plants in which the plumule has emerged an inch 



" 2 ~ 3 * 



Fig. 22. Mode of Emergence of the Cotyledons of 

 Sunflower Seedlings. 2, 3, and 4 show the region of 

 elongation {a-b) in the hypocotyl. 



or more above the soil. Beginning at the tip, make a series 

 of lines backwards as far as convenient. Make a sketch 

 true to scale and show in it the exact number of lines 

 (Fig. 22, 2). Seedlings of Sunflower and Kidney-Bean 

 (Fig. 10) serve well for this experiment. Allow them to 

 grow for a few days and note the result (Fig. 22, 3 and 4). 

 We see that the region of growth in a stem {a-b) is not 

 confined to such a small area as it is in a root. 



