different trees; and of the order Octandria, because its barren flowers have eight stamens.

a

b

B

Fig. 92.

α

A

α

a a

11th, Spadix, is an assemblage of flowers growing upon common receptacle, and surrounded by a spatha or sheath. At Fig. 92, A, a, is a representation of the blossom of the wild turnip, (arum ;) a represents the spatha, which is erect, sheathing, oblong, convolute at the base, b; and it is compressed above and below the middle; c, represents the spadix, which, from its club-shaped appearance, is called clavi-form, (from clava, a club.)

At B, is the spadix divested of the spatha; a, is the claviform summit; b, a ring of filaments without anthers; c, a ring of sessile anthers; d, a dense ring of pistillate flowers with sessile stigmas; each germ produces a one-celled, globular berry. This plant is of the class Monœcia, because its staminate and pistillate flowers are separate, but yet grow on the same plant; it is in the order Polyandria, because its stamens are numerous.

Receptacle.

The receptacle is the extremity of the peduncle, it is also called the clinanthe,* from kline, bed, and anthos, flower; at first it supports the flower, and afterward the fruit. As this is its only use, it may properly be considered in connexion with the organs of fructification. In simple flowers, as the tulip, the receptacle is scarcely to be distinguished from the peduncle, but in compound flowers it is expanded, and furnishes a support for the flowers and fruit. Receptacles are of various kinds; as,

1st. Proper, which supports but one flower, as in the violet and lily.

2d. Common, which supports many florets, the assemblage of which forms an aggregate or compound flower, as in the sunflower and dandelion. The common receptacle presents a great variety of forms; as concave, convex, flat, conical, or spherical. In the fig it is concave, and constitutes the fruit. As to its surface, the receptacle is punctate, as in the daisy; hairy, as in the thistle; naked, as in the dandelion; chaffy, as in the chamomile; it is pulpy in the strawberry, and dry in most plants.

3d. Rachis, is the filiform receptacle which connects the florets in a spike, as in a head of wheat.

Our examination of the flower is now completed. We shall, in our next lecture, proceed to consider the change which takes place, after the bloom and beauty of the plant have faded. We shall find that organs, at first scarcely perceptible, begin to develop * Sometimes torus, from the Latin, signifying bed. Spadix-Receptacle--What is the proper receptacle ?-What the common ?-What

is the rachis?

themselves, until the character of the fruit is fully exhibited. So in the heart of youth, the germs of virtue or vice may, for a while, be apparently dormant and inactive, but growing more vigorous and powerful, they at length unfold themselves, and reveal either a character matured into what is lovely and desirable, or marked with qualities of a disagreeable and deleterious nature.

LECTURE XV.

THE FRUIT-PERICARP-PARTS OF THE PERICARP-LINNEUS'S CLASSIFICATION OF FRUITS-MIRBEL'S CLASSIFICATION OF FRUITS.

The Fruit.

THE fruit is composed of two principal parts, the pericarp and seed. The term pericarp is derived from peri around, and karpos seed or fruit; it signifies surrounding the seed. All that in any fruit which is not the seed belongs to the pericarp.

Let us now inquire into the progress of the fruit from its first appearance in the germ to its mature state. When you analyze a flower, you often find it necessary to ascertain the number of cells contained in the germ. In making this examination, what appearance does the interior of the germ present, when exposed by cutting it horizontally? You see there minute bodies of a pale green colour, and an apparently homogeneous nature: each of these is called an ovule,* and their outer covering, an ovary. These ovules, before the fertilization of the germ by the pollen, are scarcely perceptible; after this period, and the fading of the corolla, the ovules increase in size, and the embryo and other parts which constitute the seed become manifest. The ovary enlarges with the growth of the ovules; the use of this covering is not confined to the mere protection of the seeds from injury, but it is furnished with glands, which secrete such juices as are necessary for the growth and development of the ovules. As the ovary becomes more mature, it takes the name of pericarp. Pericarps in their growth become either woody or pulpy; the latter absorb oxygen gas and throw off carbonic acid; saccharine juices are elaborated in their cellular integument. In another stage, the pulpy substance passes through a slight fermentation, the organization is disturbed, the juices sour, the pulp decomposes, and putrefaction ensues. Such is the change which you may see in pulpy fruits during their progress towards maturity and subsequent decay.

Parts of the Pericarp.

The germ being fertilized, the parts of the flower which are not necessary for the growth of the fruit, usually fade, and either fall off or wither away. The pericarp and seed continue to enlarge until they arrive at perfection. Every kind of fruit† you can behold has been once but the germ of a flower. The size of fruit is not usually proportioned to that of the vegetable which produced it. The pumpkin and gourd grow upon slender herbaceous plants, while the large oak produces but an acorn.

From ovum, an egg.

+ The term fruit, in common language, is limited to pulpy fruits which are proper for food; but in a botanical sense, the fruit includes the seeds and pericarps of all vegetables.

Fruit, the two principal parts-Derivation and signification of the word pericarpOvules Ovary-Use of the ovary-Its name in a mature state-Pulpy pericarpsGerm-Size of the fruit not in proportion to the plant that produces it.

In some fruits the pericarp seems to consist of three parts1st. The epicarp, the skin of the fruit, or membranous part which surrounds it, and which is a kind of epidermis;

2d. The sarcocarp,† a part more or less fleshy, corky or coriaceous, often scarcely perceptible, and covered by the epicarp,

3d. The endocarp, an internal membrane of the fruit, which lines the cavity, and by its folds forms the partitions and cells.

In the peach, for example, the skin is the epicarp; the pulpy, cellular substance which absorbs the juices of the fruit is the sarcocarp: the shell which encloses the kernel, deprived of moisture, and rendered dry and tough, is the endocarp. The endocarp is also called the putamen.

In most fruits the pericarp consists of the following parts:

1st. Valves or external pieces, which form the sides of the seed vessels. If a pericarp is formed of but one, it is univalved; the chestnut is of this kind. A pericarp with two valves is said to be bivalved, as a pea-pod. The pericarp of the violet is trivalved; that of the stramonium quadrivalved. Most valves separate easily when the fruit is ripe; this separation is known by the term dehiscence.

2d. Sutures or seams, are lines which show the union of valves; at these seams the valves separate in the mature stage of the plant; they are very distinct in the pea-pod, which has two sutures.

3d. Partitions or dissepiments, are internal membranes which divide the pericarp into different cells; these are longitudinal when they extend from the base to the summit of the pericarp; they are transverse when they extend from one side to the other.

4th. Column or Columella, the axis of the fruit; this is the central point of union of the partitions of the seed vessels; it may be seen distinctly in the core of an apple.

5th. Cells, are divisions made by the dissepiments, and contain the seeds; their number is seldom variable in the same genus of plants, and therefore serves as an important generic distinction.

6th. Receptacle of the fruit, is that part of the pericap to which the seed remains attached until its perfect maturity; this organ, by means of connecting fibres, conveys to the seed, for its nourishment, juices elaborated by the pericarp.

Some plants are destitute of a pericarp, as in the labiate flowers, compound flowers, and grasses; in these cases the seeds lie in the bottom of the calyx, which performs the office of a pericarp.

Linnæus's Division of Pericarps.

Linnæus made a division of fruits into nine classes, viz.: Capsule, Silique, Legume, Follicle, Drupe, Nut, Pome, Berry, and Strobilum.'" 1st. CAPSULE, a little chest or casket; this is a hollow pericarp which opens spontaneously by pores, as the poppy, or by valves, as the pink. The internal divisions of the capsule are called cells; these are the chambers appropriated for the reception of the seeds; according to the number of these cells, the capsule is one-celled, twocelled, &c. The membranes by which the capsule is divided into cells are called dissepiments, or partitions; these partitions are either parallel to the valves or contrary. The columella is the central pillar in a capsule; and is the part which connects the several internal partitions with the seed. It takes its rise from the recep * From epi, upon, and karpos, fruit.

† From sarx, flesh, and karpos, fruit.

From endo, within, and karpos, fruit.

Epicarp Sarocarp-Endocarp-Valves-Sutures-Partitions or dissepiments-Column-Cells Receptacle of the pericarp-Pericarp sometimes wanting-Linnæus's division of pericarps--Capsule.

tacle, and has the seed fixed to it, all around. In one-celled capsules this is wanting. (For the capsule, see Fig. 94.)

2d. SILIQUE or Siliqua, is a two-valved pericarp or pod, with the seeds attached alternately to its opposite edge, as mustard and radish. The proper silique is two-celled, being furnished with a partition which runs the whole length of this kind of pericarp; there are some exceptions to this, as in the celandine. Silicle, (silicula, a little pod,) is distinguished by being shorter than the silique, as in the pepper-grass. This difference in the form of the silique and silicle, is the foundation of the distinction in the orders of the class Tetradynamia.

3d. LEGUME is a pericarp of two valves, with the seeds attached only to one suture, or seam, as the pea. In this circumstance it differs from the silique, which has its seeds affixed to both sutures. The word pod is used in common language for both these species of pericarp. Plants which produce the legume, are called leguminous. The greater number of these plants are in the class Diadelphia. The tamarind is a legume filled with pulp, in which the seeds are lodged. 4th. FOLLICLE is a one-valved pericarp, which opens longitudinally on one side, having its seed loose within it; that is, not bound to the suture. We have examples of this in the dog's-bane, (Apocynum,) which has a double follicle, and in the milk-weed, (Asclepias.)

5th. DRUPE, (Fig. 101,) a stone fruit, is a kind of pericarp which has no valve, and contains a nut or stone, within which there is a kernel. The drupe is mostly a moist, succulent fruit, as in the plum, cherry, and peach. The nut or stone within the drupe, is a kind of woody cup, commonly containing a single kernel, called the nucleus; the hard shell, thus enveloping the kernel, is called the putamen ; the stone of a cherry or peach, may furnish an example.

6th. NUT, is a seed covered with a shell resembling the capsule in some respects, and the drupe in others; as the walnut, chestnut, &c. 7th. POME, (Fig. 102,) is a pulpy pericarp without valves, but containing a membranous capsule, with a number of cells which contain the seeds. This species of pericarp has no external opening or valve. The apple, pear, quince, gourd, the cucumber and melon, furnish us with examples of this kind of pericarp. With respect to form, the pome is oblong, ovate, globular, &c., the form of fruits being much varied by climate and soil. Every child knows that apples are not uniform in their size or figure; with respect to the number of cells also, the apple is variable.

8th. BERRY, (Fig. 104,) is a succulent, pulpy pericarp, without valves, and containing naked seeds, or seeds with no other covering than the pulp which surrounds them; the seeds in the berry are sometimes dispersed promiscuously through the pulpy substance, but are more generally placed upon receptacles within the pulp. A compound berry consists of several single berries, each containing a seed united together; as in the mulberry, (Fig. 108.) Each of the separate parts is called an acinus, or grain. The orange and lemon are berries with a thick coat. There are some kinds of berries, usually so called, that, according to the botanical definition of a berry, seem scarce entitled to the name; for the pulp is not properly a part of the fruit, but originates from some other organ. In the mulberry, the calyx becomes coloured and very juicy, surrounded by seeds like a real berry. What is commonly called the berry in the strawberry, is but a pulpy receptacle studded with naked seeds. In the fig, the

Silique-Legume-Follicle-Drupe-Nut-Pome-Berry-Compound Berry-Aci

nus-Orange and lemon--Mulberry.

whole fruit is a juicy calyx, or common receptacle, containing in its cavity innumerable florets, each of which has a proper calyx of its own, which becoming pulpy invests the seed, (Fig. 107.) The paper mulberry of China is an intermediate genus between the mulberry and fig, resembling a fig laid open, but without any pulp in the common receptacle.

9th. STROBILUM, (Fig. 105,) is a catkin or ament hardened and enlarged into a seed vessel, as in the pine; this is called an aggregate or compound pericarp. In the most perfect examples of this kind of fruit, the seeds are closely enveloped by the scales, as by a capsule. The Strobilum is of various forms, as conical, oblong, round, or ovate. The intelligent student will now perceive how much instruction may be derived from the study of the various kinds of fruits. And, although the rich gifts of God in this department of nature may be partaken of by the creatures of his bounty, with the relish which he kindly enables us to enjoy, still we cannot but feel, that in the enjoyment arising from the philosophical contemplation of these His works, there is an exercise of higher and nobler faculties. The external sense is "of the earth, earthy," the mental enjoyment may be shared with us by angels. The blessedness of heaven, we have reason to believe, will in part consist in studying and admiring the wisdom of God, as displayed in the works of his hand.

MIRBEL'S CLASSIFICATION OF FRUITS, OR PERICARPS. The following classification of fruits, by one of the most eminent botanists of the age, is given for the more advanced pupil. It is not introduced as being a part of the elements of Botany. The teacher will do well, therefore, to pass over the remainder of this lecture, leaving the pupil to read it at leisure, or to study it in the course of a reviewing lesson.

Mirbel has divided the fruits of all phenogamous plants into two classes; 1st, Gymnocarpes, which include all such as are not masked or covered by any organ, which conceals their true character. 2d, Angiocarpes, which include all fruits covered by any organ, which disguises them from observation.

CLASS I. GYMNOCARPES.

Fruits not covered.

ORDER 1st. CARCERULARES, (from carcer, a prison,) simple fruits, without valves, and which never open spontaneously. This order includes the fruits of syngenesious plants, of the grasses, &c.

Fig. 93.

Cypsela,* (from Kupselion, a coffer.) The pericarp is one-celled, one-seeded, adhering; the seed is erect, with the radicle pointing to the hilum; it is monocephalous, and crowned by the border of the calyx, prolonged in scales, in ridges, or an egret. Figure 93 represents a pericarp of this genus; it is of the syngenesious family; the pericarp (a) is turbinate, (shaped like a top;) its surface is pubescent and furrowed;

*This is the achenium, or acine, of some writers. Strawberry-Fig-Paper mulberry-Strobilum-Into what two classes has Mirbel divided fruits?-Describe the order Carcerulares-Describe the genus Cypsela.