THE VEGETATIVE ORGANS OF PLANTS. 239 
apple, peach, and other trees, when very young, in order 
that they may be readily and safely transplanted as occa- 
sion shall require. The depth and character of the soil, 
however, to a certain degree influence the extent of the 
roots and the tenacity of their hold. The roots of maize, 
which in a'rich and tenacious earth extend but two or three 
feet, have been traced to a length of ten or even fifteen 
feet in a light, sandy soil. The roots of clover, and espe- 
cially those of lucern, extend very deeply into the soil, 
and the latter acquire in some cases a length of 30 feet. 
The roots of the ash have been known as many as 95 feet 
long. (Jour. Roy. Ag. Soc., VI, p. 342.) 
2. Root-absorption.—The Office of absorbing Plant 
ood from the Soil is one of the utmost importance, and 
one for which the root is most wisely adapted by the fol- 
lowing particulars, viz.: 
a. The Delicacy of its Structure, especially that of the 
newer portions, the cells of which are very soft and absor- 
bent, as may be readily shown by immersing a young 
seedling bean in solution of indigo, when the roots shortly 
acquire a blue color from imbibing the liquid, while the 
stem, a portion of which in this plant extends below the 
seed, is for a considerable time unaltered. 
It is a common but erroneous idea that absorption from 
the soil can only take place through the ends of the roots 
—through the so-called spongioles. On the contrary, the 
extreme tips of the rootlets cannot take up liquids at all. 
(Ohlerts, Zoc. cit., see p. 249.) All other parts of the roots 
which are still young and delicate in surface-texture, are 
constantly active in the work of imbibing nutriment from 
the soil. j 
In most perennial plants, indeed, the larger branches of 
the roots become after a time coated with-a corky or oth- 
erwise nearly impervious cuticle, and the éunction of ab- 
sorption is then transferred to the rootlets. This is demon- 
