SEEDS. 
83 
for our purpose. As the pupil advances farther in his botanical studies, he will 
learn much more about them, as well as about fruits and flowers, in the Lessons 
in Botany, and other works. 
254. A seed consists of its Coats and its Kernel. Besides the true seed-coats, 
which are those of the ovule, an outer loose covering, generally an imperfect one, 
is occasionally superadded while the seed is growing. This is called an Aril. 
Mace is the aril of the nutmeg. The scarlet pulpy covering of the seeds of the 
Strawberry-tree and the Staff-tree or Waxwork is also an aril. 
255. The Seed-Coats are commonly two, an outer and an inner ; the latter gen- 
erally thin and delicate. The outer coat is sometimes close and even, and fitted to 
the kernel, as in Morning- Gflory (Fig. 227) ; some- 
times it is furnished with a tuft of long hairs, as in 
Milkweed (Fig. 229), or else is covered with long 
woolly hairs, as in the Cotton-plant, where they 
form that most useful material, Cotton-wool. In 
some cases the outer coat is extended into a 
thin border or wing, as in the Trumpet-Creeper 
(Fig. 228). Catalpa-seeds have a fringe-like wing 
or tuft at each end. The seeds of Pines are 
winged at one end (Fig. 226). All these tufts 
and wings are contrivances for rendering such seeds buoyant, so that, when shed, 
they may be dispersed by the wind. Thistle-down, and the like, is a similar con- 
trivance on the fruit or akene. 
256. The seed is often supported by a stalk of its own, the Seed-stalk. Where 
the seed separates, it leaves a mark, called the Scar or Hilum. This is conspicu- 
ous in a bean and a y>ea, and is remarkably large in a horsechestnut. 
257. Tile Kernel is the whole body of the seed within the coats. It consists of 
the Embryo , and of the Albumen , when there is any. 
258. The Albumen is a stock of prepared food, for the embryo to live upon at the 
outset, in those cases where it has not a similar supply laid up in its cotyledons 
(32 — 35, 45). In Fig. 17, 44, and 49, the seeds have albumen. In Fig. 25, 32, 40, 
and 42, they have none, but the whole kernel consists of 
259. The Embryo, or rudimentary plantlet in miniature, the body in the seed 
which grows. To this the seed, the fruit, and the blossom are all subservient. The 
albumen of the seed, when there is any, is intended to nourish the embryo when it 
