ORGANS OF FLOWERING PLANTS 1s 
part of the plant. Nevertheless, the stem, by spreading 
out the leaves, is concerned with the light and air 
relation, while, by displaying the flowers and fruit, it 
helps to relate the plant to insect and other animal 
life around it, and thus provides for pollination, and 
secures the distribution of its seed. 
1. The Root (Fig. 2) is the organ which relates the 
plant to the soil. To study the root, dig a trench round 
a mature bean plant grown in a clear piece of ground, 
and, by gradually cutting away slices from the inner 
side of the trench, observe the extent to which the 
roots explore the soil. It will be found, on nearing 
the plant, that every cubie inch of earth is penetrated 
by one, sometimes many root branches. 
By growing one plant in a plot of good garden soil, 
and another in a patch of almost pure sand, it may be 
observed how a plant adapts itself to its surroundings 
or responds to environment. Provided there is nothing 
abnormal in the season, the plant growing in soil will 
show only ordinary root development in spite of the 
unusual size and vigour of its leaves and stem; while 
that growing in the sand, though stunted as to leaves 
and stem, will produce an enormous mass of branching 
roots which leave no eranny of the soil untapped. In 
the one case there was abundant food and moisture to 
provide for growth even of the strongest shoot, while 
in the other, to find the materials necessary even for 
the much smaller stem and leaves, every soil particle 
and tiny water reservoir had to be put under contri- 
bution. This excessive production of roots was 
therefore a response to adverse ‘conditions, an 
adaptation to environment. 
Now remove several plants from the soil, each in 
a large block of earth, so that the roots may not be 
eut or broken. Then wash away the soil, preferably 
with a hose, place the root ends in a large bowl of 
