The Root and the Soit. =9 
rire) 
/ 106. Pricking Off Young Seedlings, i. e., transplant- 
ing them from their seed-box into other boxes or beds, is a 
most important preparation for their final transplanting. 
They should receive as good care after pricking off as before, 
with which, having increased room and light, they soon 
develop many new rootlets near the base of the stem, which 
need be little injured in the final removal. 
107. Nursery Trees are Greatly Benefited by Trans- 
planting them once or twice before the final planting out, 
for the reasons named in the last paragraph. 
108, Root Pruning (416) may sometimes be employed 
as a substitute for transplanting, and is especially useful in 
the case of trees that form few branch roots, as the hickory 
and walnut. | 
109. The Horizontal Extent of Roots is probably 
much greater than is generally supposed. In upright-grow- 
ing plants, the area occupied by the roots usually exceeds 
that covered by the foliage, while in spreading and trailing 
plants, the roots are probably rarely less in extent than the 
branches. It appears from the observations recorded that, 
even in such plants as the melon and squash, the horizontal 
extent of the roots usually equals or exceeds that of the 
runners. As the diffusion of soluble matters in the soil 
water is probably much hindered by the friction of the soil 
particles, the roots of plants need to travel farther after 
food than do the branches, which develop in a freely circu- 
lating medium. KHspecially is this true of plants growing 
in poor soil. 
110. The Depth of Roots in the Soil. It appears 
from the observations recorded that the extreme depth 
5 
