After sending down a root the hypocotyl began to develop into a strong
stem which crooked itself until it reached the surface of the soil and
then pulled the cotyledons or seed-leaves after it (Fig. 42). These
turn green and after a time shrink and fall off.

The pea cotyledons were left down in the soil, the epicotyl alone
pushing up to the surface. The corn pushed a slender growing point to
the surface leaving the cotyledon and endosperm behind in the soil but
still attached to the little plant (Fig. 43).


USE OF COTYLEDONS AND ENDOSPERM

=Experiment.=--Plant some beans in a pot or box of soil and as soon as
they come up cut the seed-leaves from some of them and watch their
growth for several days. It will soon be seen that the plants on which
the seed-leaves were left increase in size much more rapidly than
those from which the seed-leaves were removed (see Figs. 43 and 44).
Sprout some corn in the seed tester. When the seedlings are two or
three inches long, get a wide-mouthed bottle or a tumbler of water and
a piece of pasteboard large enough to cover the top. Cut a slit about
an eighth of an inch wide from the margin to the centre of the
pasteboard disk. Take one of the seedlings, insert it in the slit,
with the kernel under the pasteboard so that it just touches the
water. Take another seedling of the same size, carefully remove the
kernel from it without injuring the root, and place this seedling in
the slit beside the first one (Fig. 45). Watch the growth of these two
seedlings for a few days. Repeat this with sprouted peas. In each case
it will be found that the removal of the seed-leaves or the kernel