SEEDS AND THEIR GROWTH By 
At the end of the plumule is a small bud which begins: 
to unfold its leaves so soon as the light is reached. The 
cotyledons remain in the ground and gradually shrink up: 
and disappear as the plant becomes larger ; though they 
often persist for a considerable time after the plant has. 
come through the soil. The food material contained in the 
cotyledons has been absorbed by the plant and used up 
in the process of growth. 
The seeds of the pea and other plants can be examined 
and studied in the same way. 
Examination of the Maize Grain. <A Maize 
grain, which is really a one-seeded fruit, in that it 
Fig. 4.—A, Side view of Maize grain, showing position of embyro. 
B, section of same grain through aa. 
emb, embyro; rad, radicle; pl, plumule; s, scutellum ; en, endosperm ; ¢c, seed coat 
and fruit case. 
possesses both seed-coat and fruit-case, is a convenient. 
form to examine next—more suitable than the Wheat grain 
the parts of which are smaller and not so easily identified. 
It is better, therefore, to defer the examination of Wheat 
grains until the structure of the Maize grain is mastered. 
In shape a Maize grain varies considerably ; looked at 
when lying on its side, it is broad and flat, tapering 
abruptly to a point towards its base. An end view shows 
it to be wedge-shaped, broad above and gradually narrowing 
below. On one flat side is a whitish oval depression under 
which lies the embryo. 
