are arranged in one-sided racemes, in another they form small and rregular clusters. The numerous species are in most cases so aintly distinguished, as to require some patience and application to trace out the specific differences.

The genus CHRYSANTHEMUM Contains the common daisy, sometimes called ox-eye; it also includes many splendid foreign plants, mostly of Chinese origin. The Dahlia is at present a favourite with florists, who enumerate nearly a hundred splendid varieties.

Order Frustranea.

The third Order has the disk florets perfect; those of the ray are neutral, having neither stamens nor styles, though an imperfect seed is sometimes seen at the base of the florets; the name Frustranea alludes to this imperfect seed. We find here the Sun-flower, (HELIANTHUS ;) this is a very good plant to examine, as the organs are large, and develop clearly the peculiar character of the class Syngenesia.

Fig. 143, a, represents the flower of the Coreopsis; b, a floret of the disk, with its bifid stigma above the tube formed by the united anthers; c, shows a ray floret, which is neutral.

In this order is the CENTAUREA benedicta, or blessed thistle, a na tive of Spain, which received its name on account of some extraordinary virtues which it was thought to possess; it was esteemed a remedy for the plague, with which warm countries are often afflict ed. At present this plant is not much valued in medicine.

Order Necessaria.

The fourth Order includes plants in which the rays only are fertile or pistillate, and the disk florets are barren or staminate. We find here the marygold, (CALENDULA.)

Order Segregata.

The fifth Order contains a few genera, with each floret having a calyx proper to itself, besides a common calyx including the whole of the florets which make up the flower; this may be called a doubly-compound flower. The only plant of this order yet discovered in the United States is the elephant's-foot, (ELEPHANTOPUS,) a low, hairy-leaved plant, with purple, ligulate florets.

We have now completed a survey of the orders of the class Syngenesia, the plants which it contains are almost wholly referred to the natural order Compositæ or compound flowers: by Jussieu, they are subdivided into the three following orders.

Division of Compound Flowers by Jussieu.

1st, with florets all ligulate and perfect; leaves alternate, having milky juice; corollas mostly yellow. This includes the dandelion and lettuce.

2d order includes all compound flowers with tubular corollas; with receptacles fleshy and chaffy; egret stiff and bristly; leaves often with harsh prickles; flowers in a head. This includes the thistle, burdock, and false saffron.

3d order includes such compound flowers as have their inflorescence clustered in a corymb; as the life-everlasting, boneset, and

aster.

The plants of the class Syngenesia are, in general, easily recognised at the first glance; there is something about them besides their

Chrysanthemum-Dahlia-Order Frustranea-Sun-flower-Coreopsis-Blessed thistle-Order Necessaria-Order Segregata-Elephant's foot-Order CompositeJussieu's division of compound flowers.

compound character which distinguishes them from all other plants. One botanist observes, that they have a kind of "weed-like appear. ance, notwithstanding the beauty of their colouring; the stems and Leaves are often rough, and they seem to have been less completely reclaimed from their savage state, than most other plants, with the exception of the Cryptogamous class."*

Few plants of this class are poisonous; for though milky plants are generally so, those of this class are exceptions. The lettuce however contains a narcotic principle, and opium may be made from it. The dandelion, the thorough-wort, the chamomile, and wormwood, with many other plants of this class, are valued for medicinal properties.

The Syngenesious plants are particularly abundant in our own country, and you will never find difficulty in procuring specimens. If you commence botanical studies with the flowers of spring, nature gradually presents you with those that are more difficult to investigate. This class, it has been before remarked, are chiefly in blossom in the latter part of the season. Being previously prepared by a knowledge of the general principles of classification, and observations of plants, you will no doubt derive pleasure from the study of the class Syngenesia; though were you to commence a course of botany with these plants, you would feel as if thrown amidst a chaos of facts. without any clew to their classification.

Fig. 146.

LECTURE XXXV.

CLASS XVIII.-GYNANDRIA.

WE shall now examine a class in which an entirely new circumstance from any yet considered, is regarded as forming its essential character. This circumstance is the situation of the stamens upon the pistil; the stamens appearing to grow out of that organ. In some cases the stamens proceed from the germ, in others, from the style. There is sometimes difficulty in deciding as to the number of stamens, for they are not here, as in other classes, distinct organs, but in some cases mere collections of glutinous pollen, called pollinia,

Order Monandria.

The orders in this class, as in Monadelphia and Diadelphia, depend on the number of stamens, or of those peculiar collections of pollen which are called stamens. The first order of the 18th class contains such plants as have but one stamen, or two masses of glutinous pollen, equal to one stamen; this order is divided into sections, with reference to the manner in which the anther is attached to the style; as, whether it is easily separated, whether the anther grows upon the top of the stigma, and also to the shape of the masses of pollen, which are called the anther.

• Barton.

Plants of this class valued for medicinal properties-Found in the latter part of the season-Class Gynandria-Orders.

Orchis tribe of Plants.

The natural order, Orchideæ, is composed of genera whica be ong to the class Gynandria; the principal of these is the Orchis genus, the different species of which are mostly perennial, and grow in moist and shady places; some are parasites, adhering to the bark of trees by their fleshy, fibrous roots. The roots sometimes consist of two solid bulbs, in other cases, they are oblong, fleshy substances, tapering towards the ends like the fingers of the hand. The name Orchis is derived from a Greek word, signifying an olive-berry, on account of the root being round, like that fruit. The distinquishing characters of this tribe, are a corolla, above the germ, 5 petals, 3 external and 2 internal.' There is also in each corolla, a etal-like organ called the lip, which varies in form and direction; anthers always 1 or 2, and from 1 to 4-celled, sessile, or sitting upon the side or apex of the style; the pollen is easily removed from the cells in glutinous masses; the styles are simple, with viscous stigmas of various forms and positions. The capsules are 1-celled, 3-valved, 3-keeled; the seeds are numerous and dust-like, the leaves clasp the stem like the leaves of grasses. The stems or scapes are simple, and the flowers are arranged in spikes or racemes.

This natural order has monocotyledonous seeds, and stamens epigynous, or above the germ. The flowers are remarkable for their irregular, and we might add, grotesque appearance; some present the figure of a fly, others of a spider, a bird, and even of the human figure. It would seem too that the freaks of these vegetable beings are not designed for our observation, for they are as peculiar in their choice of habitations as in their external forms, preferring wildness, barrenness, and desolation to the fostering care of man, or the most luxuriant soil. It is in forests of the equatorial regions, that these plants appear in the greatest perfection. The aromatic vanilla is obtained from the fruit of a climbing orchis of those regions.

The Orchis genus has a nectary in the shape of a horn; its corolla is somewhat ringent, the upper petal vaulted, the lip is spreading, the 2 masses of pollen are concealed at the sides, by little sacs, or hooded hollows of the stigma.)

Fig. 146 represents a flower of this genus; a, shows the two masses of pollen, brought out from the cells of the anther, which is attached to the pistil.

Order Diandria

The 2d order contains the ladies' slipper, (CYPRIPEDIUM ;) the nectary or lip is large, inflated, and resembles a slipper. We have several species of this curious plant, some of which are yellow, some white, and others purple.

Order Pentandria.

The 5th order contains the milk-weed, (ASCLEPIAS ;) this by some botanists is placed in the fifth class, on the supposition that the stamens do not proceed from the pistil.

Order Hexandria.

The 6th order contains the Virginia snake-root, (ARISTOL OCHIA serpentaria,) a perennial plant, with brown fibrous roots; it is found in shady woods, from New-England to Florida: the root is highly valued in medicine; it possesses an aromatic smell, somewhat similar to spruce. It is said to have been found, by a chemical analysis,

Natural order Orchidea-Distinguishing characters of this family-Orchis-Order Diandria-Order Pentandria--Order Hexandria-Virginia snake-root.

to contain "pure camphor, a resin, a bitter extractive, and a strong essential oil." It was used by the Indians as a remedy for the bite of a snake; from this circumstance is derived its name. This plant in its medicinal properties differs essentially from the POLYGALA senega, or Seneca snake-root, and the mistaking one for the other, might, in critical stages of disease, be attended with fatal consequences.*

Order Decandria.

In the 10th order we find the wild ginger, (ASARUM ;) this is a native plant, so low that its flowers are almost concealed in the ground; the roots are creeping and aromatic, having the taste and smell of the snake-root,) (Aristolochia.)

We have now completed our view of the class Gynandria ; although many species of it are indigenous to this country, you will not so readily procure specimens of this, as of most other native plants. The ladies'-slipper, milk-weed, and dogsbane, you can often find, but many of the plants of this family, particularly the Orchis tribe, opposing all attempts at cultivation, are to be found only in the depths of the forest, or places little frequented by man like the aboriginal inhabitants of America, they seem to prefer their own native wilds to the refinements and luxuries of civilized life.

ers.

LECTURE XXXVI.

CLASSES MONECIA AND DIECIA.

In all the classes hitherto examined, we have found perfect flowOur present inquiry is to be directed to two classes, in which the flowers are imperfect, or both stamen and pistil are not found in the same individual flower. The stamens are infertile, or disappear without any fruit; the pistils contain the germ, and being fertilized by the pollen of the infertile flowers, produce the fruit.

CLASS MONECIA.

The class Monccia (one house) contains plants where, growing from the same root, we find some flowers containing only stamens, others only pistils. The orders in this class are determined by the number of stamens in each flower.

Order Monandria.

In the first order is the Bread-fruit tree, (ARTOCARPUS,) which grows to the height of forty feet, having fruit of the size of a large water-melon, hanging from its boughs like apples; it is a native of the East Indies when roasted it resembles white bread, and is much valued for food.

This plant belongs to the natural order Urtica, in which are the Fig and Mulberry.

A physician prescribed for a sick child the Seneca snake-root, (POLYGALA senega ;) the ignorant apothecary sent the Virginia snake-root, (ARISTOLOCHIA serpentaria.) The physician having fortunately remained to inspect the medicine which he had or dered, the mistake was seasonably discovered. This instance shows the importance of botanical knowledge, particularly in those who attempt to deal in medicine. Had the mother of the child understood botany, the mistake would have been discovered although the physician had not been present.

Wild ginger-Concluding remarks-In what respect do the two next classes differ from the preceding ones?-Class Monacia-Order Monandria--Bread-fruit.

Order Triandria.

In the third order we find a very common plant, called cat-tail, (TYPHA) this grows in swampy meadows, and stagnant waters, to the height of four or five feet. The long, brown spike, which grows at the summit of the stem (giving rise, from its peculiar appearance, to the name cat-tail) is the catkin; the upper part consists of sta minate flowers, having neither calyx nor corolla; the three stamens arising from a chaffy receptacle. The pistillate flowers form the lower part of the spike; each one produces a seed, supported in a kind of bristle. This plant is sometimes used by the poorer class of people for beds, but is considered by physicians as unhealthful on account of certain properties inherent in its substance. The leaves and stems of the Typha are employed for bottoming chairs and making mats; the young stalks are said to answer as a substitute for asparagus; the pollen of the flowers, which is very abundant and inflammable, is recommended by a French writer to be employed on the stage for fire.*

The sedge, or CAREX, is a genus consisting of nearly 140 known species. Though a grass-like plant, it is separated from the family of grasses, which are mostly in the 3d class, on account of the monocious character of its flowers. A treatise upon this genus, called Caricography, has been lately published by an American botanist.* This extensive genus belongs to the natural order Cyperoideæ, so called from Cyperus, one of the most important genera of the order. This tribe of coarse grasses inhabit marshy grounds; though resembling the true grasses in their general aspect, they differ from them in having stems without joints, and often triangular. Unlike the grasses, they are of little utility; they spread rapidly, and often destroy the best pastures, by overrunning them. A species of Cyperus, the papyrus, which grows in abundance on the banks of the Nile, was used by the ancients in the manufacture of a kind of thick paper. A thin fibrous membrane beneath the bark was obtained, and several thicknesses being glued together, the whole was pressed into sheets. Fragile as it was, this parchment is still to be seen in ancient records, and offers to the observation o' the curious, the autographs of Egyptians, Greeks, and Romans. (See Plate 6, Fig. 5.)

The Indian corn (ZEA mays) is found in this order. The top or panicle consists of staminate flowers only, and of course never produces corn; the pistillate flowers grow in a spike enclosed in a husk; each pistil produces a seed, called corn; the pistils are very long, forming what is called silk. This genus belongs to the natu ral order Gramineæ.

Order Tetrandria.

We here meet with the mulberry, (Morus,) whose leaves furnish nourishment to the silk-worm. The white mulberry, MORUS alba, is the species which is chiefly used for this purpose. This plant belongs to the same natural order as the bread-fruit and fig.

Order Pentandria.

The 5th order contains the genus Amaranthus, in which is a very common weed, seeming to have some analogy to the pig-weed, not only in natural properties, but in being dignified with a name which

See Plate i. Fig. 6.

+ Professor Dewey.

Order Triandria-Cat-tail-Sedge, or carex-Indian corn-What is said of the mul berry-Amaranthus.