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port of gratitude, and thanked the Author of Nature for thus beautifying the earth.
A class called Polydelphia, 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; this has its numerous stamens in three clusters, not united by their filaments; but even 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 Polydelphia (many brotherhoods), are now placed in the 12th class Polyandria (many stamens).
In the last two lectures, you will recollect 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; the orders of this class were founded on the number of stamens, and bore the same names as those classes which are founded on a similar circumstance in respect to the stamens. 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 ane piece around the column, formed by the united filaments.
In the other class, Diadelphia, we found the marks of distinction to be,
1st. The union of the filaments into two sets, 2d. The butterfly-shaped 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.
The orders of this class are founded on the same circumstance in respect to the stamens, which distinguishes those of the preceding class.
We make these recapitulations because it is always important in the consideration of a subject, to have a few clear ideas before
you leave it ; this is better than a great many imperfect or confused ones. It would, therefore, be well in all your studies, when you have read upon a subject, to ask yourselves what are the main points to be remembered; and you
Class Polydelphia, why rejected-Recapitulation-Uses of recapitulatons.
find that the less important facts or ideas, by the natural suggestions of the mind, will readily cluster around the principal ones.
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 sum. mer months, and in autumn.
The term Syngenesia signifies a union of anthers, this circumstance, you can readily conceive, forms a dif. ference between this class, and those
which are distinguished by a union of b
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 union of the anthers, but by the compound character of the flowers; the latter circumstance is indeed the essential character of the class. In some cases, plants with five stamens have their an. thers 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 irregularity. This is an instance in which the artificial arrangement is made to bend to natural resemblances.
The general characters of the compound flowers have al. ready been exhibited to you, in connexion with some of the most important and distinct natural families. The analysis of the daisy, which was illustrated by a dissected plant, must have impressed upon your minds the peculiarities which distin. guish this from all other classes.
You will recollect that a compound flower is a collection of little flowers or florets, placed upon the same receptacle, and within one common calyx; add to this description the five
Class Syngenesia-What case is mentioned in which the artificial arrangement is made to bend to natural resemblances ?
stamens, with their anthers united, forming a little tube, and you have an idea of a syngenesious flower.
The orders of the class Syngenesia are distinguished by different circumstances than are noticed in any other class; they 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.
They are also distinguished into ligulate, having a flat strap. shaped corolla, and tubular, having a tubular corolla.
The five orders in this class, depend on the various situations of these different kinds of florets.
Æqualis. The First Order contains those compound flowers which have all the florets perfect ; this order is divided into sections.
1st. Containing such as have ligulate florets; as the dande. lion, lettuce, and vegetable-oyster.
2d. Florets tubulous, with flowers in a head; as the thistle, and false saffron (Carthamus).
3d. Florets tubulous, without rays; as, bone-set, or thorough. wort (Eupatorium).
You will find no difficulty in procuring for analysis, either dandelions or thistles; bone-set is also abundant; therefore, for farther investigation of this order we will refer you to the plants themselves, aided by the generic and specific descriptions provided to assist you in analyzing plants.
Superflua. The Second order presents us with such compound flowers as have the florets of the disk perfect, and those of the ray only pistillate, each pistil producing a perfect seed. The term superflua is used, because the pistils in the ray, being unaccom. panied with stamens, are said to be unnecessary or superfluous.
This order is divided into two sections.
1st. Flowers without rays, or the ray florets indistinct; here we find the tansey, and the life everlasting; of the latter there are many species.
The ARTEMISIA, a genus which includes the wormwood and southern-wood, both exotics, has but few native species. The name Artemisia is often improperly given to an ornamental
Orders, how distinguished ?-Different kinds of florets-Order Æqualis divided into three sections-Order Superflua—Two Sections Artemisia.
plant, which belongs to the genus Chrysanthemum. « The genus Artemisia, was named in honour of Artemis, the wife of Mausolus, whose monument was one of the wonders of the world (hence our word Mausoleum). Pliny observes that wo. men have had, also, the glory of giving names to plants."*
The 2d section of the order Superflua, includes such flowers as have flat or ligulate petals, arranged around the middle or disk of the flower; these are called rays.
The receptacles in this section are naked, that is, the top of the stem is found, on removing the different parts of the blossom, to be smooth, with. out any hairs or down, such as you may see on the dandelion after the petals have fallen off. We here find the star flower (ASTER), a genus in which 120 species have already been discovered, more than 60 of which are natives of the U. States. These are not often seen in blossom until June and July; they appear in flower until the approach of winter. Many of these flowers are highly beautiful ; the different species present a great variety of rich and delicate colouring, from the dark blue, purple, and red, to a pale blue, a light violet and pink, and in many cases, a pure white. In some, the yellow prevails ; sometimes they are variegated, and often the disk and ray are of different colours. . After having once become familiar with the Aster genus, you will seldom fail to distinguish it; but it is often difficult to determine the species. If you meet with obstacles in this, you are not to consider your time as lost; comparison and research strengthen the mind, and the greater difficulties you overcome, the greater will be the advantage, in thus accustoming yourselves to nice comparisons, and close investigations.
The golden rod (SOLIDAGO) is a numerous genus; the different species are mostly yellow; in one section of these plants the flowers are arranged in one-sided racemes, in another they form small and irregular clusters. This genus will also afford an opportunity of strengthening the mental faculties by over. coming difficulties; for its numerous species are in most cases so faintly 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 mountain daisy (Bellis) is the flower which you were taught to analyze under the head of compound flowers.
* Thornton's British Flora.
Aster-Advantages of overcoming difficulties in the analysis of plants Golden rod-Chrysanthemum.
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 develope very clearly the peculiar character of the class Syngenesia.
Fig. 121, 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 native of Spain, which received its name on account of some extraordinary virtues which it was thought to possess, such as being a remedy for the plague, with which warm countries are often afflicted ; at present this plant is not much valued.
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).
Segregata. The Fifth Order contains a few genera, with each floret hav. ing 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, ligu. late 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 three orders.
Divisions of Compound Flowers by Jussieu. 1st, with florets all ligulate and perfect, leaves alternate, hav. ing 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 inflo.
Order Frustranea-Sun-flower- Explain Fig. 120_Blessed thistle-Order Necessaria-Order Segregata, Elephant's foot-Order Composite-Jussieu's division of compound flowers.