THE ROOT. 33 
. 
89. PERENNIAL roots are those of plants which bear leaves 
and flowers during many successive years, as trees, and many 
herbaceous plants: but the term is more generally applied 
to those roots which annually send forth herbaceous stems, 
which flourish and die in one season: Asparagus. The an- 
nual stem dies down to the neck or life-knot, from which, in 
the ensuing season, another arises, the root having retained 
its vitality. 
90. The small fibres, which terminate the plant inferiorly, — 
are supposed, in every case, to be annual, being destroyed 
by the cold of winter, and renewed in spring to perform 
their important functions. 
91. Hence the proper period for transplantation is during 
winter, when the plant is in a manner in a torpid state, be- 
fore it has begun to throw out new fibres. Should the air 
be full of moisture at the time, new fibres may be formed in 
time to prevent the injury of the tree by evaporation, as this 
goes on slowly in a moist atmosphere. In a dry atmosphere, 
the juices are so quickly dissipated that the plant will be 
seriously injured before new spongioles can be formed to 
supply the loss by evaporation. 
92. Some annual roots vegetate for two years or more, 
when transferred to a warmer climate and a richer soil : and 
perennial plants frequently become annual when transferred 
from a warm to a cold climate. The Castor-oil plant (Rici- 
nus communis or Palma Christi), the Mignonette (Reseda 
odorata), and the Indian Cress (Tropeolum majus), are per- 
ennial, or even woody trees or shrubs in their native coun- 
tries, but annual in our cold climate. 
_ 98, According to their form and structure, roots have 
been divided into seven kinds, the Fibrous, the Creeping, the 
Fusiform, the Abrupt, the Tuberous, the Bulbous, and the — 
all that part of a plant which is under the surface of the 
situation and form of the a ee referred to, 
Granulated. When these kinds of roots are spoken of, it 
‘must be borne in mind, that, by the term Root, is meant Ze 
