THE SEED. 169 
embryo, that is, the germ of a new individual, a rudimentary plant 
in miniature, which will soon present all the characteristics of the 
parent plant, whose species it is to perpetuate. The embryo is 
composed of cells and spiral vessels; a small stem, or stalklet; a 
rudimentary descending portion, which becomes the root or radicle; 
and a rudimentary ascending axis, surmounted by a bud, or gem- 
mule. Between the radicle and the gemmule, the first leaves 
developed are termed cotyledons: a plant having leaves like seed- 
lobes. Fig. 259 shows these different parts in an embryo of the 
Almond-tree. When the plant has only one germinating leaf, or 
cotyledon, as the Ricinus (Castor Oil-plant), (Fig. 260), Wheat- 
plant, Tulip, Palm, and Pond-weed (Fig. 261), we say that the 
embryo and the plant are monocotyledonous ; when there are two, 
as in the Rose, Almond-tree (Fig. 262), and the Bean, we say that: 
they are dicotyledonous. : 
The cotyledons of the Ricinus (Fig. 260) are very thin, and 
offer, on their surface, very distinct traces of veins ; they resemble 
small leaves, while those of the Almond-tree and the Bean are 
thick and fleshy, and present nothing like a leaf at first sight. 
They have undergone deep and essential modifications, appropriate 
Nesom MEER TELE ne pa pe 
to the functions they are called on to perform in the act of 
germination. 
Tn a great number of cases the kernel is exclusively formed by 
the embryo, that is, the entire seed is made up of the embryo, and 
integumentary covering only. But there is often developed, 
either around, or by the side of the embryo, an accessory and com- 
pletely independent body, which is a sort of reservoir of nutritious 
