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THE ROOT 
which they penetrate. This is an adaptation for holding 
the plant more securely than the ordinary roots could do. 
When mature, they branch freely. 
Adventitious roots are those which grow from unusual 
places, especially soil roots. It is the ability to form such 
roots that enables us to “ slip ” plants like geraniums, 
balsams, ivy, and Wandering Jew. Such garden plants as 
Figure 244. — Root System of Alfalfa. 
How far from the stem of the plant do you think the roots extended ? 
tomato, cucumber, squash, and others, put forth adventitious 
roots where their stems touch the soil, especially at the nodes 
in the case of the vines named. This is an adaptation which 
gives them a greater supply of food material near the leaves 
which use it, and which enables the plant to live even if 
broken from the main portion of the stem. 
Certain cactus plants which live in the desert have roots 
which are twenty times as long as the parts which appear 
