54 NATURE STUDY AND AGRICULTURE 
use. In this practice, however, plants vary greatly. In 
annual plants like the grains, we have no such storage, for 
it would be sheer waste. The best illustrations 
are seen in such biennials as beets, turnips, car- 
rots, and parsnips. These roots literally gorge 
themselves with food during their first year, and 
if allowed to grow the following season, this 
nourishment is used in the production of large 
seed-bearing plants. There are also many per- 
ennials, as rhubarb, asparagus, and peonies,whose 
vigorous growth in early spring is made possible 
by the abundant nourishment that was stored in 
their fleshy roots the previous year. 
Tue LEAVES 
Function of Leaves.— Leaves are indispen- 
sable for the growth of plants, and in autumn, 
after they have died, the plant is dormant, that 
‘ is, its life processes are suspended. A careful 
Fiesay Roots study of the work of leaves requires some knowl- 
Asparagus. edge of chemistry as well as of botany, and a 
very brief statement must suffice here. We may say that 
they serve (1) as the breathing organs, and (2) as the work- 
shop of the plant. 
1. As breathing organs they take in useful material (carbon 
dioxide) from the air and cast off waste material (water and 
oxygen) into the air. 
2. The leaf is the workshop where the raw materials, 
taken from the air by the leaf itself and from the soil by the 
roots, are converted into starch, out of which all other plant 
tissues are made. This is a very complicated manufacturing 
process, and it is marvelous that it is carried on so silently 
