The CALYX, (8,) or flower cup, is mostly green, and intended to defend the rest of the flower before the time of blossoming. It is, therefore, always the outer covering, and when the flower has but one coat, this is called a calyx, whatever may be its color, size, or shape. Thus the beautiful cup of the Tulip is a calyx, composed of six leaves, or as they are called sepals. The COROLLA, (9,) or blossom, is the colored part of a flower, next within the calyx. It is well known as the most beautiful portion. We recognize the corolla in the red petals or leaves of the Rose-the scarlet of the Poppy, and the purple of the Violet. Its use is supposed to be to defend the inner parts, and to reflect upon them more fully the rays of the sun. Some persons think to attract the insects also. The folding up of the corolla, and of the calyx, before expansion, is called their æstivation. The NECTARY, (10.) The true meaning of this word is a place to secrete honey, but the term is given to every casual appendage to the flower, which is neither calyx nor corolla, and which does not appear to be necessary to the production of the seed. The nectary is often very beautiful: it is seen in the rays of a Passion flower, the cup of a Narcissus, and the spur or horn of a Lark's-spur. In the Violet it is also a spur. The PISTIL, (11,) or pointal, is always in the centre of the whole flower. When fully formed, it consists of the germ or young seed-vessel at the lower part; next, the thread-like portion called the style; and at the top of this the stigma, which is usually knobbed and sticky. Sometimes there are more styles than one, and then the top of each is a stigma. In other cases the style is wanting, and then the top of the germ itself is the stigma. The use of the pointal is to collect the pollen from the stamens, and to convey it to the young seeds in the germ, without which they do not become perfect. The STAMENS, (12 and 13,) are the parts seen between the corolla and the pointal. They are attached sometimes to the corolla, at others to the calyx, and in some plants to the pointal. A stamen consists of a thread-like portion, called the filament, and of a thicker club-shaped part, called the anther or pollen case, the use of which is to perfect and produce pollen for the supply of the pistil. The PERICARP, (14 and 15,) seed vessel or fruit, now ripe and opening to scatter the perfect seeds within. It is seen divided or burst into three parts or seed valves, having a row of seeds in each. Before it thus opens the pericarp is a nearly round body, with one cavity or cell, and which, if cut across, will show the seeds to be attached in three rows, equally distant from each other. A seed consists of a thick coat or skin, called the axil. This being peeled off will exhibit two equal lobes, seed leaves, or cotyledons, connected together by a small bud, called the embryo. This structure is to be seen very easily in the common Bean or Pea. A few plants are furnished with more than two cotyledons, as Fir trees-numerous others, as the Grasses and Lilies, have but one. The above account of vegetable structure is but a general description, without entering into the almost endless variations of shape, size, or texture, that each part assumes in different plants. Leaves, for example, are distinguished by their shapethe cuts upon their edges-the difference of their points-their manner of growth-the nature of their surface, and very many other particulars, each of which is known by an appropriate name—such as long, downy, stalked or toothed. In like man ner, the stem may be solid or hollow, square or round, hairy or smooth, &c. The roots, calyces, corollas, and other parts, are equally subject to variation; or one of them may be entirely absent. Thus many plants are stemless-others without leaves. Some have no calyx or corolla, and whole tribes have neither nectary, stipule, bract, or any other appendage. The stamens and pistils are, however, never absent, as without them no seed could be produced; and as all plants arise from seed, so their absence would imply the extinction, at no very distant period, of all such defective races. Instead of this being likely to arise, we see that the whole existence of a vegetable is a series of the most wonderful contrivances for the production of seed, similar to that from which it sprung. The wonders of form and function do not even cease here. It is proper that that seed should be scattered around in places suited to its growth- should be defended from casual injury, and should be assisted in its first germination, while as yet the plant is too young and feeble to gather its own food. All these necessities are fully provided for, and in a manner which calls for our highest admiration, as so many instances of that Divine intelligence, which, by such simple means, can form so endless a variety of perfect and beautiful objects, and distribute them over the earth for the benefit of animals of a still higher organization. [The details of vegetable structure and organization, as well as botanical classification and geography, is fully explained in the Author's "Grammar of Botany," price 4s.] THE NATURAL SYSTEM OF BOTANY. A system of botany is an arrangement of plants into varieties, species, genera, orders, classes, &c. An accidental difference constitutes a variety—a natural difference in leaves, roots, &c., makes a species-a still greater difference, especially if it relate to the flower or fruit, shows that each is of a distinct genus or family. Some common marks of similitude collect the genera into tribes, orders, classes, or other assemblages. For example, the white Raspberry is a variety of the red Raspberry, which is a species of Bramble. The Brambles differ from the Roses, Strawberries, Apples, and Cherries, in fruit, therefore they are of a distinct family or genus; yet as all these agree in flowers, and other particulars, they all belong to the same tribe, class, &c. The use of a system of botany is to point out these various particulars, and so to arrange them as to direct our attention from one to another, until we are able to assign to every plant its proper station among others to discover its name, understand its structure, and learn its probable virtues. This is only to be done by what is called the natural system, invented by De Jussieu, and improved by De Candolle, and others. By this system plants are arranged into classes, sub-classes, divisions, orders, and tribes; and afterwards into genera, species, and varieties, according to the following tables, which apply only to the plants afterwards to be described. It is to be observed, that the name of the order is mostly taken from the name of some plant within it. Flowering plants are divided first into two classes, Endogens and Exogens, distinguished as under : ENDOGENS Have leaves with parallel veins, mostly running from the base to the point of the leaf-stems which are hardest on the outside, with little or no real wood, and seed growing with only one lobe or cotyledon, or if two, growing alternately with each other. They are also called monocotyledonous plants. The sub-classes are two-Glumosa, which includes such plants as have dry, husky flowers, like the Grasses; and Petalosæ or those with flowers composed of petals, like plants in general. The following are the principal orders of ornamental endogynous plants, commonly cultivated, with their characters : 1-Graminaceæ....Flowers dry and husky; stems round and hollow. 4-Liliaceæ ......Flowers wholly petaloid, inferior; stamens 6. EXOGENS Have leaves with netted veins stems which are hardest towards the centre, mostly consisting of bark, wood, and pith; and seeds furnished with two or more lobes or cotyledons. They are also called dicotyledonous plants, and include all trees, shrubs, and most fibrous-rooted herbs. This extensive class is separated into two sub-classes, and the latter of these into four divisions, which with their chief orders are as follows: Sub-class I. MONOCHLAMYDEE. ONLY. FLOWERS WITH CALYX 7-Lauraceæ....Calyx 4 or 6 cleft; stamens 9 or 6. (Trees or shrubs.) 8-Thymelaceæ ..Calyx 4 cleft; stamens 8 or 4. (Trees or shrubs,) 9-Polygonaceæ ..Seed 3 cornered; stipules sheathing the stem. 10-Nyctaginaceæ.. Calyx tubular, joints of the stem swollen. 11-Amaranthaceae.. Calyx dry, 3 or 5 leaved; stipules none. Sub-class II. DICHLAMYDEA. FLOWERS WITH CALYX Division 1. AND COROLLA. Stamens growing on the corolla. 12-Labiatæ.......... Fruit superior, of 4 distinct nuts; corolla irregular. 13-Boragineæ ...... Fruit superior, of 4 distinct nuts; corolla irregular. 14-Verbenacea...... Fruit superior, 2 or 4 celled; corolla regular. 15-Scrophulariaceæ.. Fruit superior, 1 celled; corolla irregular. 16-Plumbagineæ Fruit superior, 1 celled; seeds solitary; styles 5. 17-Primulaceae.. Fruit sup., 1 celled; seeds many, attached to a column. 18-Gentianacea.. Fr. sup., 1 celled; seeds many, attached to side valves. 19-Polemoniaceae.. Fruit sup., 3 celled; seeds many, attached to side val. 20-Lobeliaceæ.. Fruit sup., 3 celled; seeds many; flowers irreg.; stam. 5. 21-Convolvulaceae.. Fruit superior, 2 celled; seeds few; corolla plaited. 22-Solanaceæ.. Fruit superior, 2 celled; seeds many; corolla imbricated. 23-Apocynaceae.. Fruit superior, a double follicle; corolla twisted. 24-Ericaceæ-Fruit superior, 3 celled; seeds many; stamens 8. 25-Jasminaceæ.. Fruit superior, 2 celled; seeds 1 or 2; stamens 2. 26-Campanulaceæ.. Fruit an inferior, 1-celled, many-seeded capsule. 27-Caprifoliaceæ.. Fruit inferior, mostly pulpy; leaves opposite. 28-Stellatæ.. Fruit inferior, of 2 single-seeded carpels; leaves whirled. 29-Valerianaceæ.. Fruit inferior, of one pappose seed; solitary. 30-Dipsaceæ.. Fruit inferior, collected into heads; stamens distinct. 31-Compositæ.. Fruit inferior, collected into heads; stamens united. |