THE VEGETABLE GARDEN 211 
GERMINATION OF SEEDS 
Parts of seeds. A seed consists of the enbryo (a minia- 
ture plant commonly called the germ) and its coverings. 
The seed coat of the bean is called 
the testa. The little opening in the 
Micropyle__ 
Hilure testa, which may be found by squeez- 
ing a seed that has been soaked, is 
known as the micropyle. The place 
where the seed was attached to the 
pod is called the hilum (see Fig. 112). 
The embryo of the bean 
has three parts: the small 
stem, or hypocotyl; the 
seed leaves, or cotyledons ; 
Fic. 112. Lima Bean 
and the bud, or plumule. 
Food material for the sup- 
port of the 
young plant 
is stored in the cotyledons (see Fig. 113). 
After cracking the shell-like seed coat 
of the castor bean we find that the part 
within is covered with a delicate mem- 
Fic. 113. Lima Bean opened 
Lengthwise 
brane, the inner seed coat. The food 
Fic.114. ACastor material within this coat contains the 
ie very thin cotyledons, that absorb the 
food stored around them. When the food material is 
stored on the outside of the cotyledons, as in the castor 
bean, it is known as endosperm (see Fig. 115). 
