THE ROOT 53 
it gives rise to the whole root system of the plant. In 
the maize, on the other hand, though the radiele may 
lengthen considerably and branch to a certain extent, 
it remains thin and fibrous and forms but a portion 
of the root system. Shortly, adventitious roots (i.e., 
roots not given off in regular succession from a tap 
root) arise from the stem at the bases of the lower 
leaves. 
If a box of the kind deseribed is not available, a 
olass jar lined with blotting paper and filled with moist 
sawdust may be used, the seeds being placed between 
the blotting paper and the glass. 
In the bean, and indeed most dicotyledons, the 
elongated radicle forms the primary or tap root, 
which bores deep into the soil, and, by throwing off 
secondary, which in their turn give rise to tertiary 
roots, forms a root system of great extent. Indeed,. 
the branching may be continued indefinitely till almost 
every soil particle in the neighbourhood of the plant 
is in contact with the hairs of one or more of the 
spreading rootlets. The adventitious roots of the 
maize or any other monocotyledon, form, on the other 
hand, a dense fibrous mass, and, though the fibres 
thoroughly explore a certain soil region, they do not 
penetrate so deeply as the root of the ordinary 
dicotyledonous plant. 
There are, however, even dicotyledons in which the 
tap root,after penetrating the earth for a little distance, 
goes no further, but leaves to its branches the work 
of gathering the food the plant requires. These surface 
feeders are well seen in the forest undergrowth, where 
they flourish side by side with the mighty trees, deep- 
feeders that make their way to the lower strata of the 
soil. Thus every soil-region is laid under contribution. 
The oak is a deep-feeder and the pine a surface-feeder. 
Hence, while the former is hardly ever uprooted even 
