Some plants creep by their tendrils to a very great height, even to the tops of the loftiest trees, and seem to cease ascending, only because they can find nothing higher to climb. One of our most beautiful climbing plants is the CLEMATIS virginica, or virgin's bower, which has flowers of a brilliant whiteness. Its pericarps, richly fringed, are very conspicuous in autumn, hanging in festoons from the branches of trees, by the sides of brooks and rivers.

8th. Pubescence includes the down, hairs, woolliness, or silkiness of plants. The pubescence of plants varies in different soils, and with different modes of cultivation. The species in some genera of plants are distinguished by the direction of the hairs. The microscope is often necessary in determining with precision, the existence and direction of the pubescence. It has been suggested that these appendages may be for similar purposes as the fur, hair, and bristles of animals, viz. to defend the plants from cold, and injuries from other

9th. The Bract, or floral leaf, is situated among, or near the flowers, and is different from the leaves of the plant. You may, in Fig. 66, observe the difference between the real leaves (b, b,) and the bract (a;) the former being cordate and crenate, the latter lanceolate and entire.

In some plants, as in several species of sage, the transition from leaves to bracts is so gradual, as to render it difficult to distinbguish between them, and a considerable part of the foliage is composed of the bracts. In the crown-imperial, the stem is terminated by a number of large and conspicuous bracts. These appendages are sometimes mistaken for the calyx. Bracts are green or coloured, deciduous or persistent. The orchis tribe have green leaf-bracts. No plants of the class Tetradynamia have bracts.

We have, in regular order, considered the first of the two classes of vegetable organs, viz.: such as tend to the support and growth of the plant, including root, stem, leaf, and appendages; we shall next examine the class of organs whose chief use appears to be that of bringing forward the fruit.

LECTURE XI.

CALYX.

We are now to consider the second division of vegetable organs, viz.: such as serve for the reproduction of the plant, called organs of fructification. Their names were considered when commencing the analysis of flowers; but we are now to examine them with more minute attention, and to remark upon their different uses in the vegetable economy.

You are no doubt pleased to have arrived at that part of the plant, which is the ornament of the vegetable kingdom. Flowers are dePubescence-Bract-Difference between the real leaf and the bract-Recapitulation -Second division of vegetable organs.

lightful to every lover of nature; a bouquet, or even the simplest blossom, presented by a friend, interests the heart. How many pleasant thoughts are awakened by the fresh and perfumed incense which ascends from flowers!-their odour has been poetically termed, the language by which they hold communion with our minds. Females are usually fond of flowers; but until recently, the greater number have only viewed them as beautiful objects, delighting the senses by their odour and fragrance, without being aware that they, lovely as they seemed, might be rendered doubly interesting, by a scientific knowledge of the relations and uses of their various parts. Even at the present period, there are those who spend years in cultivating plants, ignorant of their botanical characters, when a few hours study might unfold to them the beautiful arrangement of Linnæus, and open to their mental vision a world of wonders.

Although every part of a plant offers an interesting subject for study, the beauty of the blossom seems, by association, to heighten the pleasure of scientific research. Flowers are indeed lovely, but like youth and beauty they are fading and transient; they are, however, destined for a higher object than a short-lived admiration; for, to them is assigned the important office of producing and nourishing the fruit; like them should the young improve the bloom of life, so that when youth and beauty shall fade away, their minds may exhibit that fruit, which it is the business of youth to nurture and mature. Calyx.

The calyx is frequently wanting; as in the lily and tulip. The corolla is also wanting in many plants; as, in most of the forest trees, which, to a careful observer, may seem to produce no flower; but the presence of a stamen and pistil, is in botany considered as constituting a perfect flower. These two organs are essential to the perfection of the fruit; and when a flower is destitute either of stamens or pistils, it is termed imperfect. A flower is said to be incomplete when any of the seven organs of fructification are wanting.

The word calyx is derived from the Greek, and literally signifies a cup; it is the outer cover of the corolla, and usually green; when not green, it is said to be coloured. This organ is an expansion of the bark of the flower-stalk, as appears from its colour and texture. The calyx usually envelops the corolla, previous to its expansion, and afterward remains below or around its base. Sometimes the calyx consists of one leaf or sepal only, it is then called monosepalous; when it consists of several distinct leaves, it is called polysepalous; when one calyx is surrounded by another, it is double; when one calyx belongs to many flowers, it is common.

In the calyx are three parts, very distinct in calyxes which are long and cylindric; these are, 1st, the tube which rises from the base; 2d, the throat, above the tube; and 3d, the mouth, or the upper and 'expanded part; the tube of the calyx is cylindric in the pink, and prismatic in the stramonium.

The position of the calyx with respect to the germ offers an important mark of distinction between different genera, and also bètween different natural families of plants. The calyx is said to be superior when it is situated on the summit of the germ, as in the apple; it is inferior, when situated below the germ, as in the pink. In many plants the calyx is neither superior nor inferior, but is situated around the germ.

Flowers delightful-Many who cultivate them ignorant of their botanical characters-Flowers analogous to youth-Calyx, sometimes wanting-Description of the calyx-Parts of the calyx-Position with respect to the germ.

When the calyx drops off before the flower fully expands, it is called caducous; the petals of the poppy are, at first, enclosed in a calyx of two large green leaves, but these fall off before the flower is full blown. When the calyx withers and drops off with the corolla, it is called deciduous. In many plants it remains until the fruit is matured; it is then called persistent. Upon a pea-pod, for example, the calyx may be seen as perfect as it was in the blossom. On examining an apple or pear, the dried leaves of the calyx may be seen on the top of the fruit; this shows that the calyx was superior, as well as persistent.

According to the divisions of Linnæus, there are seven kinds of calyxes; viz.

Perianth, Involucrum, Ament, Spatha, Glume, Calyptra, Volra. Perianth. This term is derived from the two Greek words, peri, around, and anthos, flower. This is the only real calyx or cup, as the term cup does not properly apply to the other kinds. A good example of the perianth calyx is presented in the rose, where it is urn-form, with divisions at the top resembling small leaves. In the pink, the perianth is long and tubular, having the border dentate or toothed. The holly-hock, hibiscus, and many other plants, have a double perianth. The term perianth is often used when a flower has but one envelope, as in the tulip; and more especially in cases where it is difficult to determine whether this envelope should be called a corolla or calyx.

Involucrum. This term is derived from the Latin, involvo, to wrap up; this kind of calyx is usually found at the base of an umbel, as in the carrot. It is said to be universal, when it belongs equally to the whole of an aggregate flower; and partial,* when it encloses one floret which, with others, constitutes a compound or aggregate flower. The term involucrum is also applied to the membranous covering in the fructification of ferns.

Ament or catkin, is a kind of calyx, by some classed as a mode of inflorescence; it consists of many chaffy scales, ranged along a thread-like stalk or receptacle; each scale protects one or more of the stamens or pistils, the whole forming one aggregate flower. The ament is common to forest trees, as the oak and chestnut; and is also found upon the willow and poplar. In some trees, the staminate flowers are enclosed in an ament, and the pistillate in a perianth.

Spatha, or sheath. It is that kind of calyx which first encloses the flower, and when this expands, bursts lengthwise and often appears at some distance below it. The wild turnip, or Arum, furnishes an example of this kind of calyx, enclosing a kind of inflorescence called a spadix, (Fig. 67. a.) From the peculiar appearance of the spadix as it stands up surrounded by the spatha, it is sometimes called Jackin-the-box. The spatha is common in many of our cultivated exotics, as in the Narcissus, where it appears brownish and withered, after the full expansion of the flower. You see here a re+ See Fig. 91.

*See Fig. 128, a, a. Duration-Different kinds of calyxes-Perianth-Involucrum-Ament-Spatha.

presentation (Fig. 67) of the Spatha of the Arum (b,) and of the Narcissus, (c.) In the Egyptian Lily, the spatha is white and permanent, and the stamens and pistils grow upon different parts of the spadix. Palms have a spadix which is branched, and often bears a great quantity of fruit.

Glume, is from the Latin word gluma, a husk. of the grasses, and grass-like plants. In the oat

This is the calyx and wheat it forms the chaff, a part which is thrown away as worthless. In the oat, (Fig. 68,) the glume calyx is composed of two pieces called valves; in some kinds of grain of but one, in others of more than two valves. To the glume belongs the awn or beard. The corolla of grasses is husky, like the calyx, and is sometimes considered as a part of it. Some botanists consider that there is in the grasses, neither calyx nor corolla, and that these scales are only membranous bracts.

Fig. 68.

Calyptra. This term is derived from the Greek, and signifies a veil. It is the cap, or hood, of pistillate mosses, resembling in form and position, the extinguisher of a candle.*

Volva, the ring, or wrapper of the fungus plants. It first encloses the head of the Fungus, afterward bursts and contracts, remaining on the stems, or at the root.†

We have now considered the different kinds of calyx. We find that this organ is not essential, since it is wanting in some plants, but its presence adds to the completeness of the flower; in some cases it is the most showy part; as in the Lady's-ear-drop, where it is of a bright scarlet-colour, and in the Egyptian Lily, where it is pure white.

The calyx is of use in protecting the other parts of the flower before they expand, and afterward supporting them in their proper position. Pinks, having petals with long and slender claws, which would droop or break without support, have a calyx. Tulips having firm petals, and each one resting upon a broad strong basis, are able to support themselves, and they have no calyx. In some plants, the calyx serves as a seed-vessel; as in the order Gymnospermia, of the class Didynamia, where there are four seeds lying in the bottom of the calyx.

LECTURE XII.

COROLLA.

THE term Corolla, or corol, is derived from the Latin, corona, a crown or chaplet. As the calyx is formed by a continuation of the fibres of the outer bark, the corolla is a continuation of the inner coat of the same. The texture of the corolla is delicate, soft, watery, and coloured. It exhales carbonic acid gas, but not oxygen, neither in the dark, nor when acted upon by light. The cuticle, or outward covering of the corolla, is of an extremely fine texture. The rich and variegated colours of flowers, are owing to the delicate organization of the corolla; and to this cause the transient duration of this organ may also be attributed.

The corolla exhibits every variety of colour except black; florists sometimes present us with what they term black roses, and we see some other flowers which approach this colour, yet none are perfectly black; the darkest being but a very deep shade of purple. Corollas are white, yellow, blue, violet, &c.; in some, different colours are delicately shaded, and blended; in others, they meet abruptly, without any intermediate teint. The colour of the corolla, in the same species, often varies without any assignable cause. This fact is strikingly illustrated in the Four o'clock, (MIRABILIS;) the flowers of which are sometimes of pale yellow, sometimes bright crimson, and often richly variegated. These varieties are the result of circumstances not under the control of man; the florist watches these charges, and, as far as possible, avails himself of them in the production of new beauties in the vegetable kingdom.

The corolla, before blossoming, is folded in the calyx, as the leaves are within the scales of the leaf-bud, and the whole is then called the flower-bud. In most cases, the calyx and corolla are so distinctly marked, that it is perfectly easy to distinguish them. The colour usually constitutes a very striking mark of difference; the calyx being ordinarily green, and the corolla of a more lively hue. But the colour is not always a criterion, for in some cases the calyx is beautifully coloured. In the Fuscms, (Lady's ear-drop,) the calyx is of a briglit scarlet; you might at first think it to be the corolla; but if you remove the scarlet coat, you may see, wrapped around the eight stamens, a purple covering; on taking off each piece carefully, you will find four petals,* as distinct as the petals of a rose; you will then perceive that the outer covering must be the calyx.

Linnæus made the following distinction between the corolla and the calyx; viz. that the corolla has its petals alternate with the stamens, and the calyx has its leafets arranged opposite to them. This rule is not found to be invariable; it has led some botanists to call that the corolla which others have named the calyx. It seems that we must come to the conclusion that nature has not placed any absolute limits between these two organs.

The corolla sometimes falls off soon after the flowering, as in the poppy; it is then said to be caducous; sometimes it fades and withers upon the stalk, as in the blue-bell; it is then said to be marescent, or withering.

* Some botanists call these nectaries, but this seems to be making an unnecessary confusion in terms; for they have as much the appearance of petals, as those of a rose or pink.

Corolla-Description of the corolla-Its situation before expanding -How distinguished from the calyx ?-Rule of Linnæus-Duration.