140 ROOTS 
and the Dandelion, where the shoots die down in the fall to be 
followed by new ones in the spring. Thus the tap-root system 
is well adapted to the perennial habit. In some plants, as 
Radishes, Beets, Carrots, Turnips, 
etc., where the storage function is 
quite prominent, the tap-root is 
tender and of much importance as 
a vegetable. (Fig. 125.) From some 
fleshy roots valuable products are 
extracted, notably the Sugar Beet 
from which most of our sugar is ob- 
tained. 
Plants having prominent tap-roots 
with short lateral roots can be grown 
close together without injury. Due 
to this fact and to the size of the 
shoot, such plants as Clover, Alfalfa, 
Beets, and others with the tap-root 
system grow well when crowded. 
The fascicled root-system, consisting of a cluster of roots all of 
which are much enlarged in connection with the storage of food, 
is characteristic of a few plants of which the Sweet Potato and 
Dahlia are two that are well known. (Fig. 126.) 
Adventitious roots, so named because of their occurrence in un- 
accustomed places, may be 
mentioned here, although 
the classification pertains 
to the place of occurrence 
and not to any peculiar fea- 
ture of the root itself; for 
any root, whether fleshy or 
fibrous, developing from 
leaves or from stem regions 
where roots are not nor- 
mally present is called ad- 
Fie. 125. — Sugar Beet, a 
plant with a fleshy tap-root. 
ys Fic. 126. — A portion of a Sweet Potato 
ventitious. All r oots may plant, showing the fascicled roots. 
be regarded as adventitious 
except those, known as the primary ones, which develop directly 
from the radicle of the embryo. 
The ability of many shoots to develop roots from various re- 
