88 
MANUAL, OF NATURE STUDY. 
The second use of the roots is to fix and hold the 
plant in the ground, or natural sub-stratum. In 
most cases the same roots perform both offices, as 
bean roots, corn, ragweed, hogweed, any kind of 
tree. Corn roots may be an exception, in that after 
jointing, this plant sends from a lower node a 
whorl of braces called aerial roots, whose chief office 
is that of guy rope to the top-heavy corn stalk. 
Some plants, such as creeping vines that grow 
to cover a whole side of a stone or brick church, 
have two kinds of roots: one kind in the ground to 
draw nourishment from the soil, the other the 
clinging roots which attach themselves to the stone 
wall for support. To prove that these clinging 
roots do not absorb food supply, cut off the upper 
part of the vine from its source of supplies in the 
earth, and that part will soon wither and die. 
To prove that the roots in the earth do not 
give mechanical support to the stalk, remove the 
vine from its fastenings in the wall, and that plant 
will immediately fall to the earth. 
In fleshy roots, such as radish, turnip, parsnip, 
etc., aside from mechanical and vital suppport to 
the plant, a third use is required, viz.: that of stor¬ 
ing up starch, fat, sugar and other reserve mate¬ 
rials to be drawn upon by the plant at another 
period in life. 
