494 
The Seed and its Germination. 
delicate testa, which shows a mark or hiluni at its base or broad 
part. This hilum is the point of attachment of the seed. The 
micropyle is present in this seed as in the former case, but, 
instead of being near the hilum, it is at the apex of the seed. 
If the testa be now carefully removed, it is seen to have covered 
a mass of white matter. Cautiously scraping this with a needle, 
it will be found to enclose a yellowish body placed rather to one 
side of it. This is the embryo. It is smaller proportionately 
than is that of the bean, and the cotyledons, instead of being 
thick and fleshy, are thin and leathery, and are rolled round 
part of the floury white matter. The latter is the endosperm. 
A section through the buckwheat seed is shown in fig. 2. 
In the castor-oil seed the embryo is situated in the middle of 
the endosperm, and the cotyledons are flattened out. The seed 
has a very brittle testa, which can be picked off" piecemeal. After 
removal of this, the seed may be split in two by a cut along its 
sides, when each half will show a cotyledon adhering to a mass 
of endosperm. A section in this plane is shown in fig. 4, and 
another at right angles to this in fig. 5. 
The barley or wheat grain is not easy to dissect, because its 
testa cannot readily be removed. The testa of the seed and the 
pericarp of the fruit are adherent together, and the endosperm is 
closely attached to the rind so formed. After soaking, however, 
a section through the grain will show the relation of the parts. 
If a wheat grain be examined, there will be found on the convex 
side, at thejbase of the grain, a small brown spot or patch of oval 
shape. This indicates the position of the embryo. A clean sec- 
tion through this spot, in the direction of the furrow in the front 
of the grain, will bring to light the features described above, but 
the parts are too small to be identified without the aid of a 
microscope. An enlarged drawing of a grain of barley so dis- 
sected is shown in fig. 6. 
The resumption of activity involves a call upon the reserve 
materials to furnish the necessary pabulum for the development 
of the body of the embryo. Before its growth was arrested, 
the parent plant was the source of such supply, but now it is 
severed from the parent, and dependent only on itself. In 
later life it can lay its environment, or surroundings, under 
contribution, but as yet it has no organs available for this work. 
In the seed, whether in the endosperm or in the embryo 
itself, these reserve materials are found in what are called cells. 
The whole of the structure, embryo and endosperm alike, is 
made up of a large number of these bodies, some extremely 
simple in structure, others considerably modified, as in t be 
covering of the scutellum. A vegetable cell of the simplest 
