Tlie Seed and its Germination. 
491 
the link between the old anil the new individual. Springing 
from the one, it contains within itself the germ of the other, 
a germ which, though partially developed, is yet dormant, and 
may remain so for a time almost indefinite in its duration. 
Yet, though dormant, it possesses life, and changes of which we 
know nothing may be taking place in its substance. After a 
certain time, the length of which varies extremely, changes in 
its environment may, and do, bring about changes in its inner 
vital condition, which lead to the resumption and perfection of 
the development which was begun while it was still connected 
with its parent, but which was afterwards suspended till the 
onset of germination. 
The seed of a plant is thus essentially the new individual, 
not quite indeed at its starting point, but developed only so 
far as to show within itself the several features of the plant — 
the representatives of stem, leaves, and root. It is furnished 
with a mass of reserve material, which will be utilised on the 
resumption of active life. The essential properties of a seed 
are all comprised in these two factors — the resting rudimentary 
plant or embryo, and the food materials which the latter will 
by-and-by require. 
The mode of distribution of these materials is by no means 
uniform in seeds, and a distinction between two main kinds is 
usually made. In the one the skin, or testa, as it is called, is 
found to contain the embryo only, which is then usually of 
large size. Such a seed we find in the common pea or bean. 
If it be freed from its testa and dissected, we 
can observe the young root curling over a fleshy 
mass, which is easily separable into two parts 
symmetrical with one another (see fig. 1). These 
fleshy masses represent the first leaves, and are 
known as the cotyledons, or seed-leaves. In such 
a seed they are the storehouses of the reserve Fig. l.—Seed of 
materials, and their consistence is due to the Fea dusected - 
n , i l-i j ■ i "i • M • c. cotyledon ; r, radi- 
masses ot these which are deposited m their c ie, or young root ; 
substance. Between them, when they are gently ^T^l 0 ™ 11 
forced apart, can be seen the rudiment of the 
young stem. All leguminous seeds (clover, sainfoin, lucerne, 
vetches, &c.) and all cruciferous seeds (turnip, rape, cabbage, 
kale, mustard, radish, &c.) are of this type. 
Other seeds show an additional structure present besides the 
embryo and the testa. The embryo is in them found to be 
embedded in a mass of homogeneous-looking material, which 
may be floury, or fleshy, or even horny in its consistence. This 
is technically known as the endosperm, or albumen, and is a 
K K 2 
