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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 tubu. lar, having the border dentate or toothed. The holly-hock, hi. biscus, and many other plants have a double perianth. The general remarks which were made upon the calyx may be con. sidered as chiefly applicable to the perianth.

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 par. tial 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 ag. gregate flower. The Ament is common in forests trees; as in the oak and chesnut; and is also found in the willow and poplar. In some trees, the staminate flowers are enclosed in an ament, and the pistillate in a perianth.

Spatha, signifies a sheath. It is that kind of calyx which first encloses the flower, and when it 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. From the peculiar appearance of the spadix, as it stands up surrounded by the spatha, it is sometimes called Jack in the pulpit. The spatha is Fig. 47.

common in many of our cultivated exotics, as in the daffodil (NARCISSUS) where it appears brownish and withered, after the full ex. pansion of the flower. You see here a representation (Fig. 47), of the spa. tha of the arum (b), and of the Narsissus (c). In the Egyptian Lily, the spatha is white and permanent and the stamens and pistils grow separately upon the spadix.

[graphic]

Involucrum- Ament-Spatha

Palms have a spadix which is branched, and often bears a great quantity of fruit.

Fig. 48.

Glume, is from the latin word gluma, a husk. This is the calyx of the grasses, and grass like plants. In the oat, and wheat, it forms the chaff, a part which is thrown away as worthless. In the oat (Fig. 48), the glume calyx is composed of two pieces or 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. A French Botanist says, that there is in the grasses, neither calyx nor corolla, that these scales are only membranous bracts. He thinks, the confusion with respect to those parts has tended to render the study of grasses difficult.

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, or curtain; the ring or wrapper of the Fungus plants. It first encloses the head of the Fungus, afterwards bursts and contracts; remaining on the stems, or at the root.

We have now considered the different kinds of calyx; we find that the calyx is not essential, since it is wanting in some plants, but its presence adds to the completeness of the flower; and in some cases it is the most showy part; as in the Lady’sear-drop, where it is of a bright scarlet colour, and 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 afterwards supporting them, by keeping all in their proper position.

Pinks having petals with long and slender feet, which would drop or break without support, have a calyx. Tulips having

Glume Calyptra—Volva- Uses of the calyx.

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 naked 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 cellular integument, or inner coat of the same. The texture of the corolla is delicate, soft, watery, and coloured. It exhales carbonic acid gas, but does not give off oxygen, either in the dark, or when acted upon by light; as is the case with the green parts of plants. 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, its transient duration 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 tint.

The colour of the corolla, in the same species, often varies without any assignable cause. This fact is strikingly illustra. ted in the Four o'clock, (Mirabilis,) the flowers of which are sometimes of a pale yellow, sometimes a bright crimson, and often richly variegated. Man does not create these varieties; they are the result of circumstances unperceived by him, and not under his controul ; the florist watches these changes, 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 corol.

Corolla - Derivation of the term A continuation of the cellular integument - Description of the corolla-Colour-Its situation before expanding.

la are so distinctly marked, that it is perfectly easy to distin. guish 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. In some cases the calyx is beautifully coloured. In the Fuschia, (Lady's ear-drop,) the calyx is of a bright scarlet; you would, no doubt, 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 see 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 as if nature had 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.

Each simple part, of which the corolla is composed, is called a petal. A flower with petals is said to be petalous ; without petals, it is called apetalous. The petals are definite when their number is not more than twenty ; they are said to be indefinite when they exceed that number.

If the corolla is formed of one single piece, or petal, it is monopetalous ; if of more than one, it is polypetalous. You may sometimes find a difficulty in determining whether a corolla is in one piece or more ; for monopetalous flowers often have deep divisions, extending almost to the base of the corolla; but they must be divided at the base, or be in separate pieces, in or. der to be considered as polypetalous. It is a good rule to consider the parts into which a corolla naturally falls, as so many petals.

Monopetalous corollas (see Fig. 50), consist of the tube, throat and limb. The tube is the lower part, having more or less the form of a tunnel. The throat is the entrance into the tube; it is either open, or closed by scales or hairs. The limb is the upper border of the corolla.

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

How distinguished from the calyx ?~Rule of Linnæus- Duration-Parts of the corolla- Monopetalous-Polypetalous corollas, how divided ?-Forms of monopetalous corollas.

a

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Fig. 49.

Polypetalous corollas consist of several petals. Each petal consists of two parts, the lamina and claw.

The lamina (Fig. 49, a), is the upper and usually the thinner part of the petal ; its margin is sometirnes entire, ôr without divisions, as in the rose ; sometimes notched, or crenate, as in the pink. The lami. na corresponds to the limb of monopetalous corollas.

The claw (Fig. 49, ), is the lower part of the petal, and inserted upon

the

receptacle; it is sometimes very short, as in the rose ; in the pink, as seen at Fig. 49, it is long and slender. The claw is analogous to the tube of monopetalous corollas.

The corolla is superior when it is inserted above the germ ; inferior, when below. It is regular when each division corresponds to the other. The rose and pink have regular corollas. When the parts do not correspond with each other, a corolla is irregular, as in the geranium, pea, and labiate flowers.

Different forms of Mono petalous Corollas. Monopetalous corollas may, according to their forms, be divided as follows. Fig. 50.

1st. Bell-form (campanulate, from campanula, a little bell); the tube is not very distinct, as the corolla gradually spreads from the base ; as in the blue bell, hair bell, &c. At Fig. 50 is the representation of a bell-form corolla ; it is monopetalous; the limb (a)

is five parted; calyx (6) five parted; b

corolla superior.

[graphic]

Fig. 51.

2d. Funnel form (infundibuliformis, from infundibullum, a funnel), having a tubular base, and a border opening in the form of a funnel, as the morning glory (Fig. 51).

Polypetalous-Corolla, superior-Inferior-Regular-Irregular-Bell-form - Funnel-form.

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