OUTLINES OF BOTANY. XXXVli 
§ 14. The Seed. 
161. The Seed is enclosed in the pericarp in the great majority of 
flowering plants, called therefore Angiosperms or angiospermous plants. In 
Conifere and a very few allied genera, called Gymnosperms or gymnosper- 
mous plants, the seed is naked, without any real pericarp. These truly 
gymnospermous plants must not be confounded with Labiate, Boraginee, 
etc., which have also been falsely called gymnospermous, their small nuts 
having the appearance of seeds (158). 
162. The seed when ripe contains an embryo or young plant, either fill- 
ing or nearly filling the cavity, but not attached to the outer skin or the 
seed, or more or less immersed in a mealy, oily, fleshy, or horn-like sub. 
stance, called the aljwmen, or perisperm. 'The presence or absence of this 
albumen, that is, the distinction between albuminous and exalbuminous seeds, 
is one of great importanee. The embryo or albumen can often only be found 
or distinguished when the seed is quite ripe, or sometimes only when it be- 
gins to germinate. 
163. The shell of the seed consists usually of two separable coats. The 
outer coat, called the testa, is usually the principal one, and in most cases 
the only one attended to in descriptions. It may be hard and ecrustaccous, 
woody or bony, or thin and membranous (skin-like), dry or rarely succulent. 
It is sometimes expanded into wings, or bears a tuft of hair, cotton, or wool, 
called a coma. ‘The inner coat is called the zeginen. 
164. The fuwnicle is the stalk by which the seed is attached to the pla- 
centa. It is occasionally enlarged into a membranous, pulpy, or fleshy ap- 
pendage, sometimes spreading over a considerable part of the seed, or nearly 
enclosing it, called an aril. A strophiole or caruncieis a similar appendage, 
proceeding from the testa, by the side of or near the funicle. 
165. The hilum is the scar left on the seed where it separates from the 
funicle. The micropyle is a mark indicating the position of the foramen of 
the ovule (183). 
166. The Bmbryo (162) consists of the adicle or base of the future 
root, one or two Cotyledons or future seed-leaves, and the Plumule, or future 
bud within the base of the cotyledons. In some seeds, especially where 
there is no albumen, these several parts are very conspicuous, in others they 
are very difficult to distinguish until the seed begins to germinate. Their 
observation, however, is of the greatest importance, for it is chiefly upon 
the distinction between the embryo with one or with two cotyledons that are 
founded the two great classes of phenogamous plants, Monocotyledons and 
Dicotyledons. | 
167. Although the embryo lies loose (unattached) within the seed, it ts 
generally in some determinate position with respect to the seed or to the 
whole fruit. This position 1s described by stating the direction of the 
radicle next to or more or less remote from the hilum, or it is said to be 
superior if pointing towards the summit of the jruit, inferior if pointing 
towards the base of the frwit. 
§ 15. Accessory Organs. 
168. Under this name are included, in many elementary works, various 
external parts of plants which do not appear to act any essential part 
either in the vegetation or reproduction of the plant. They may be classed 
under four heads: TZendrils and Hooks, Thorns and Prickles, Hairs and 
Glands. 
