The orders in the class Diadelphia, like those of the preceding class, are founded upon the number of stamens.

Order Pent-Octandria.

We could not expect from the character of the class, "stamens united into two sets," to find any plants with but one stamen. Those with five or eight stamens are all placed in one order called Pentoctandria, (five and eight stamens ;) here we find the Corydalis, an elegant plant with bulbous roots; the corolla is rather ringent than papilionaceous. Fumaria is nearly allied to Corydalis by natural characters. In some cases the stamens have very broad bases, and scarcely seem united in this class. We find here POLYGALA, one species of which is called Seneca snake-root; this not only produces a beautiful flower, but is valuable in medicine. many species of this genus in our woods and meadows.

Order Decandria.-Leguminous Plants.

We have

The tenth Order is wholly composed of plants with leguminous pods; the general character of these plants is, a calyx, often 5-parted, corolla 5-petalled, inserted on the calyx, and consisting of a banner, two wings and a keel; stamens generally 10, mostly united into two sets, 9 and 1; germ free; style 1; legume generally 2-valved, 1celled, sometimes transversely divided into many cells; seeds affixed to the edge on one side.

At Fig. 141, a, is a flower of this kind; b, shows the stamens divested of their petals; c, shows the pistil, the germ already exhibiting the form and appearance of the legume.

In this large family of plants with leguminous pods are many genera of great importance in the vegetable kingdom; but when we are able to give striking natural characters, there seems to be less need of particularizing each genus. The form of the corolla and the nature of the fruit, with few exceptions, settle the character of this class.

The most savage nations usually pay some attention to Diadelphous plants. When Ferdinand de Soto marched his army into Florida, before the middle of the 16th century, he found the granaries of the natives "well stored with Indian corn and certain leguminous seeds;" which were probably the Lima bean, (Dolichos,) or some species of that genus, for the natives still continue to cultivate them.

The bean and pea tribes are found here. They consist of several different genera, as the vetch plants, Vicia, in which are many cultivated species, and the indigenous one, Americana. The Phaseolus, or kidney-bean, has its native as well as exotic species. The pea, so much valued as a table vegetable, belongs to the genus Pisum, a species of which, called Beach-pea, is found upon the shores of lakes and the sea-coast. The rattle-box (Crotolaria) with its inflated pericarp, is a favourite with children, who find it on sandy plains; it is a low pubescent plant with yellow blossoms. Of clover (Trifolium) there are many species, as the red, yellow, white, &c. The locust tribe contains many ornamental shrubs and trees.

The indigo (Indigofera tinctoria) of warmer climates, the red sandal-wood of the East Indies, the liquorice, and the sensitive plant, are all of this class. The gum-arabic is obtained from the acacia of the Nile, (Mimosa nilotica.) The liquorice of commerce is ob

Order Pent-Octandria-Corydalis-Polygala-Order Decandria-General character of plants of this order-Savages cultivate these plants-Bean and pea tribe--Indigo, liquorice, &c.

tained by boiling the roots of the Glycirrhiza, a native of Italy and France. The tamarind is a native of tropical regions. The Arabians and Africans allay their thirst by the cooling freshness of the pulp contained in its legumes. Some plants of this class seem to possess active properties; the seeds of the Lupine are said to be poisonous. A traveller states, that the banks of the Nile are often visited in the night by the hippopotamus or river-horse, a large animal which does great damage to the gardens and fields; and that the inhabitants destroy the animal by placing a quantity of the Lupine seeds near where he is expected; these he devours greedily; they soon swell in his stomach, and distend it so much as to cause death.

The Furze (ULEX Europaeus) is a very common plant in Europe, though not found so far north as Sweden. It is a flower of beautiful appearance; so much so, that Linnæus, as is said, when he first beheld it, fell upon his knees, in a transport of gratitude, and thanked the Author of nature for thus beautifying the earth.

A class called Polyadelphia, or many brotherhoods, having stamens united in more than two sets, was formerly admitted, but it was thought to be unnecessary, and the genera which it contained have been transferred to the class Polyandria; the St. John's wort (Hypericum) is among the plants which were in the rejected class Polyadelphia; this has its numerous stamens in three clusters, not united by their filaments; but all the species of the Hypericum are not thus divided into separate parcels of stamens. This distinction, as the character of a class, is very properly laid aside; and the plants which were in the former 18th class, Polyadelphia, (many brotherhoods,) are now placed in the 12th class, Polyandria, (many stamens.) In the last two lectures, we have treated of two classes distinguished by the union of their filaments. In one class, Monadelphia, the general character was that of filaments united in one set, forming a tube. In this class, no particular form of the corolla was found to be general, unless we except the last order, in which the hollyhock flowers may serve as an example; having a double calyx of an unequal number of divisions, a corolla of five heart-shaped petals, united into one piece around the column formed by the united fila

ments.

In the class Diadelphia we found the marks of distinction to be, 1st. The union of the filaments into two sets;

2d. The papilionaceous corolla; and,

3d. The nature of the fruits, consisting of that kind of pod called a legume, and thus forming one great natural family of Leguminous plants, which furnish many of the most delicious table vegetables; such as peas, beans, &c.

LECTURE XXXIV.

CLASS XVII.-SYNGENESIA.

We have now arrived at a class which contains a large portion of the vegetable tribes, particularly of those plants which blossom in the last summer months, and in autumn.

Furze-Class Polyadelphia, why rejected?-Recapitulation of the last two lectures -Class Syngenesia.

The term Syngenesia signifies a union of anthers; this circumstance, you can readily conceive, forms a difference between this class and those which are distinguished by a union of filaments; in the one case, the tops of the stamens, or the anthers, are united, while the lower parts are separate; in the other case, the tops are separate, while the filaments, or lower parts of the stamens, are united.

The number of stamens in plants of this class is mostly 5, distinguished from the fifth class not only by the compound character of the flowers, but by a union of Fig. 143. anthers. In some cases, plants with five stamens have their anthers united, but having no other resemblance to those of the class Syngenesia, they are retained in the fifth class: the violet and impatiens are examples of this irregulari- . ty. This is an instance in which the artificial arrangement is made to bend to natural resemblances.

The term compound relates to the arrangement of the flowers, which are so closely connected as to have the appearance of one single flower. From the union of their stamens, these flowers are also called Syngenesious. The compound flowers have, by botanists, been distinguished under the three heads of semi-flosculous, (having ligulate florets ;) flosculous, (having tubular florets ;) and radiated, having tubular florets in the centre and ligulate at the circumference; the latter florets are called rays.

The semi-flosculous division contains a milky juice, which is bitter and of a narcotic quality; as the lettuce (Lactuca) and dandelion; their florets are all of one colour. The flosculous division usually exhibit in the leaves and roots a predominance of the bitter principle, as the burdock, (Arctium ;) their florets are also of one colour. The radiated division is mostly composed of plants called Corympiferous, (from corymb and fero, to bear,) because their flowers are corymbs, as the Chrysanthemum, Aster, &c. This division includes many beautiful flowers, with splendid colours; and also affords many medicinal plants, as tansey and bone-set, (Eupatorium.) The colour of the florets in the disk and ray is often different in these flowers.

The compound flowers begin to blossom in the latter part of summer, and are found bordering upon the verge of winter. The dandelion is among the earliest flowers of spring, and one of the latest of autumn. The daisy is found in almost every spot which exhibits any marks of fertility; these are not single flowers, like the violet or rose, but crowded clusters of little florets.

The sun-flower is so large and conspicuous' as doubtless to have frequently attracted your notice. If you examine one carefully, you will find it to be composed of more than a hundred little flowers, each as perfect in its kind as a lily, having a corolla, stamens, pistil, and seed. We distinguish the sun-flower into two parts,-the disk, which is the middle of the flower, and supposed to have resemblance to the middle or body of the sun; the ray is the border of the flower, or those florets which spread out from the disk, as rays of light diverge from the sun. The florets in this, as in other compound flowers,

What does Syngenesia signify? What are the characteristics of this class ?-How are the compound flowers divided?-Describe these divisions-Dandelion and daisy -Describe the sun-flower.

do not all begin to expand at the same time, they usually begin at the disk and proceed inwards towards, the centre. If you examine with a microscope, one of the florets of the disk, you will perceive it to be tubular, containing one pistil surrounded by five stamens, which are separate; but the five anthers grow together, forming a tube around the pistil. It is this union of anthers which gives to it a place in the class Syngenesia. The florets of the ray are called neutral, having neither stamens nor pistils; the circumstance of neutral florets in the ray, places the sun-flower in the order Frustranea, of the 17th class.

Although the term compound is confined to the flowers of the class Syngenesia, the real circumstance on which the class is founded is not the compound character of the flower, but the union of the anthers. A Clover blossom may in one sense be called compound, as it is a collection of many little flowers united; but each little floret of the clover has its own calyx; there is no general calyx enclosing the whole, as in most of the Syngenesious plants, but the florets are arranged in such a manner as to form a head; the anthers are separate, the filaments connected at their sides; and this lattér circumstance, together with the papilionaceous form of the corolla, places the clover in the class Diadelphia.

Most of the Syngenesious flowers are composed of two sorts of florets, either tubular, with a toothed margin; or strap-shaped, (ligu late,) flat, but being also toothed at the edge; the latter are sometimes called Semi-florets, or half flowers.

Analysis of the Daisy.

Fig. 144 represents the mountain daisy: we will consider its different parts.

1. The Root, (a;) this is fibrous; see the small threadlike parts issuing from the main root, or radix; from these fibres sometimes spring out little tubercles, it is then said to be fibrous-tubercled.

2. The Leaves, (b;) these spring from the root, and are hence called radical; being undivided, they are called simple. In form, they are somewhat oval, with the narrow end towards the stem; this form is called obovate. The leaves are said to be ciliate, on account of the hairs upon their margin.

3. The Stem (c) is called a scape, because it springs directly from the root, and bears no leaves; it is simple and pubescent.

4. The Calyx (d) is hemispherical; it is common, that is, a enclosing many florets; the leafets of the calyx, sometimes called scales, are equal.

Is a clover blossom a compound flower?-Two sorts of florets in most of the com

pound flowers-Describe Fig. 144.

5. The Corolla (e) is compound, having many florets on one receptacle, radiate, having rays; the florets of the disk are tubular,

a

Fig. 145.

(Fig. 145, a ;) they have both stamens and pistils; they are funnel-shaped, and fivetoothed; the florets of the ray (b) are flat, and have pistils without stamens.

6. The Stamens (c) are five, united at the summits by their anthers, forming a tube.

7. The pistil in the disk florets passes up through the tube formed by the anthers, (d) the stigma is parted into two divisions, which are reflexed; the pisti in the ray florets passes up through the tube.

8. The plant has no pericarp or seed vessel; the seeds grow upon the receptacle, (e) they are single and shaped somewhat like an egg; they are also naked, that is, destitute of the downy plume called egret, which is seen upon the dandelion, and. many other of the syngenesious plants.

9. The receptacle is conical, or resembles in shape a sugar-loaf; it is dotted with little holes; these are the places in which the seeds were fixed; the appearance of the receptacle, whether naked or chaffy, is very important to be observed in the syngenesious plants; it sometimes constitutes a distinction between genera. The seed belongs to Mirbel's genus of fruits, Cypsela.

The botanical name of the daisy is EELLIS perennis. It belongs to the class 17th, Syngenesia, because the anthers are united; order 2d, Superflua, because the pistils in the ray are superfluous, having no stamens. The generic name, Bellis, is from an ancient Latin word, belles, handsome; from which comes also the French word bel; the specific name, perennis, signifies that it is a perennial plant, or one whose roots live several years.

The common name, daisy, is derived from a property which many petals of the syngenesious plants possess of folding themselves at the setting of the sun, and expanding them with its rising. The poet Chaucer, who lived in the fourteenth century, is said to have first noticed this circumstance, and to have called the flower Day's-eye. The orders of the class Syngenesia are founded on the situation of the several kinds of florets. We will, however, before explaining the orders, remind you of the distinction made in these florets 1. Perfect, such as have both stamens and pistils.

2. Barren, or staminate, having only stamens.

3. Fertile or pistillate, having only pistils.

4. Neutral, destitute of either stamens or pistils.

They are also distinguished into ligulate and tubular.

The five orders in this class depend on the various situations of these different kinds of florets.

Order Equalis.

The first Order contains those compound flowers which have all the florets perfect; this order is divided into three sections.

Describe the corolla of the daisy-The stamens-The pistil-The pericarp-The receptacle-Botanical name, class, and order of daisy-Derivation of the botanical name The common name-Orders of the class Syngenesia, how distinguished ?-Different kinds of florets-Order Equalis, divided into three sections.