ROOTS eS tt 
soil should be taken up with the plant, in order that the 
root-hairs may not be injured and the plant not wither 
away. : 
Definition A root of a land plant may now be defined as 
of a Root. that part of the plant which fixes it in the soil, 
and absorbs nourishment for it through its branches, which 
—_ aredeveloped laterally, and 
are exactly similar to it in 
structure. 

Adventitious Roots which 
Roots. do not arise 
from the radicle are said 
to be adventitious. They 
may be developed from 
the stem, as in ivy, where 
they become — climbing 
organs through their clasp- 
ing power. ‘Cuttings ” 
put out roots from the cut 
stem, and even flowers in 
water will send out roots 
from their cut stalks: 
Marguerite daisies com- 
monly do this. 
The aerial roots of 
tropical Orchids are also 
adventitious; in this case 
the dust and drops of dew 
and other moisture falling 
on the root furnish the plant with food. Thus, an Orchid 
with aerial roots, although it lives on another plant, generally 
some tree, does not in any way injure it, for it gets its 
nourishment from the air and not at the expense of the tree. 
Some tropical trees, the Banyan-tree, for example, give out 
roots from their trunk ; these hang down like long streamers, 
at first swinging freely in the air, but eventually taking root 
in the ground. It is said that the island of Barbados received 

Fic. 14.—Frsrovus Roots oF GRASSES, 
