THE PLANT 
‘OST plants familiar to us grow from seeds. 
The germ, swelling under the influence of 
heat and moisture, gradually bursts the seed, 
the little root descends in the soil, and the 
primary leaves expand in the air. 
Seeds are of different kinds: some contain 
a horn-like substance called albumen, in which the germ or em- 
bryo lies imbedded; others are entirely filled by the cotyledons 
or seed-lobes of a fully developed plant. When the embryo is 
very small and the albumen fills the entire seed, the germination 
is generally slow and more uncertain than when the fully devel- 
oped plant has merely to straighten out and grow, as in the 
common maple. ‘The baby plants derive their first nutriment 
from the stored-up matter in the fleshy seed-leaves or the 
abundant albumen, but soon assimilate food taken up in the 
ordinary way from soil and air. 
The root, gradually branching, penetrates the soil in all di- 
rections, and by means of numerous exceedingly fine hairs just 
above the growing-point, absorbs nutriment dissolved in water. 
This nutriment and water ascends as sap to the leaves where, 
under the action of heat and light, it is assimilated and becomes 
available as food. Roots are very different in shape and qual- 
ity. Some are almost hair-like, white and delicate ; others are 
