Tue Catryx. The calyx, cadvé, “the cup which holds the flower,” is the external envelope of the flower. It has neither the elegant shape nor the varied colours of the corolla, usually appearing as a little 8reen cup, on which the corolla rests. On account of its appear-

ance and colour, it is almost always confounded with the peduncle, of which it appears to be a mere prolongation, an expansion which afterwards subdivides into several lobes. The simple form of the calyx is suited, however, to its functions. It is, in general, not elegance or delicacy, but firmness and solidity, which are able to protect or defend. As the calyx forms the external envelope of the flower, it must be constituted so as to resist action from without. It is true that the calyx of some plants, such as the Fuchsia (F ig. 157), rivals the corolla in elegance and beauty, but these are exceptions to the general facts. _ The calyx is, then, the external envelope of the flower, and its different parts bear the ) name of sepals.: / These sepals, however, are only modified leaves. If we glance at the Camelia-bud (Fig. 158), the same structure, the same nervature, almost the same form, will be observed to belong both to the five sepals of

Fig. 157.~The Fuelwia. the flower, and to the bracts accompanying them. In the Peony, and Foxglove (F ig. 159), there is still a resemblance, or rather an insensible transition, between the bracts

| and the sepals. When we notice the various

transitions of appearance, form, and size between bracts and leaves, we are led of necessity to consider the calyx of flowers as proceeding from 4

| modification of the leaves. ;

The calyx seems sometimes to be formed all in one piece, and sometimes it is more or less deeply divided. In the former case it is monosepalous, the latter it is polysepalous. The flower of the Primrose (Fig. 160) has @

Fig. 158.~Calyx of Monosepalous calyx, that of the Flax-plant (Fig-the Camelia. Ancient authors considered the calyx as an entire organ, which was sometimes cut more or less deeply. To this false idea we owe

the defective expressions, strap--shaped, scalloped, lobed, dentated, &c., by which the free parts of the leaflets of the calyx joined in one whole have been described.

The intersections, in fact, do not reach from top to bottom. When a calyx begins to show itself, its elements, ‘| the sepals, are always free. In a polysepalous calyx they remain isolated until fully developed, but if the calyx is monosepalous, they are supported up to a certain point by a sort of belt.

Without dwelling here on the different shapes the Fig. ooser of sepals assume, we will content ourselves with statin that these organs become indistinguishable in the Valerians (Fig. 162) and Groundsel (Fig. 163), and a host of other similar plants. They appear in these plants like a bunch of silk or hair called a tuft, and if we did not arrive at, this curious modification by a series of appropriate examples, it would be very difficult to ascribe to the sepals their real origin.

The number of sepals in a calyx is extremely variable. There are two in the Celandine, three in, the Virginian Spider-wort, four in the Willow-herb, five in the Hellebore, six in the Barberry, and a considerably eeeMoniaepa number in the Cacti.

With regard to their arrangement on the receptacle, the sepals are sometimes in a whorl (or verticil), that is, several placed at

ee161.ip rag Fig. 162,—Tufted Calyx of Valerian. Fig. 163.—Tufted Calyx of of Linum, Groundsel.

the same level, if the receptacle is conical, or at an equal distance m the centre, if the receptacle is flat; some are disposed

spirally, that is, at different heights, so that the line uniting their’ bases is a spiral.

it Sepals are, in short, either alike in size, inserted at the same height or distance, free or united, or else they do not show a perfect agreement in these points, and thus determine whether the calyx be regular or irregular. That of the Money-wort (Fig. 164) is regular, and that of the Aconite (Fig. 165) is irregular. In the Poppy, the calyx falls before the a flower blows, in the Ranunculus it is not de-

Fig. 164.—Regular calyx of tached until after the fecundation of the flower. rae i In the Physalis it remains round the fruit, very much enlarges, and becomes of a yellow or reddish colour.

This last phenomenon of colouration brings us to a reflection which has its interest. In some cases

of a corolla. The calyx of _ appearance the Pomegranate and that of the Fuchsia and of the calyx of Aconite. are red, that of the Larkspur Fig. 165.—Irregular Aconite are blue. The calyx may thus be coloured even when the corolla is wanting.

THE Corona.

All that we have said about the charming sweetnessof flowers applies particularly to the corolla, for on that organ nature lavishes her brightest colours. In spite, however, of the beauty and elegance of shape which we admire in it, the corolla is only the immediate envelope of more important organs, which with the help of the calyx, it protects against the action of external causes. When the fundamental phenomenon of fecundation is effected: when the fertilised ovary begins to enlarge, and can of itself oppose a sufficient resistance; then nature, which suffers nothing useless to exist, throws away this graceful decoration: the corolla fades, withers, and falls. If it remains occasionally a short time after fecundation, it is probably only to reflect the rays of external

heat, and concentrate them on the fettilised ovary, thus accelerating its development.

The corolla is the inner envelope of the essential organs of the flower. It differs generally from the calyx in being of a more delicate tissue. The corolla alone constitutes the flower in the eyes of the world generally, but to a botanist the stamens and pistil are the essence of the flower, for under the influence of the stamens the pistil produces fruit, the seeds of which will perpetuate the species. The petals are organs which, when taken together, constitute the corolla. They take their rise, like sepals, from modified leaves, a fact which is easily established. In some flowers, the Calycanthus, for instance, the petals are so completely shaded off with the sepals, that it is impossible to say where the calyx ends or where the corolla begins. In fact, the external divisions of these flowers are of a greenish hue, the internal parts being of a purple tint;but it is impossible to allot the intermediate divisions to one of the floral envelopes more than to the other. As the petals are

Fig. 166.—Petal of Fig. 167.—Petal of Fig. 168.—Petal of the Fig. 169.—Petal of Aconite.

Dielytra, Fennel, Columbine.

shaded off into the sepals, the latter intoae bracts, and the bracts into the leaves, we must conclude from this fact also that the ‘petals are really modified leaves.

Like leaves, petals offer to us very different forms and most varied dimensions. They are generally either linear, oblong, elliptical, oval, or rounded. Sometimes they are boat-shaped,

as in the Blumenbachia insignis. Sometimes they take the form of a spoon, as in the Dielytra spectabilis (Fig. 166); sometimes they show two lips, as in the Fennel-flower (Fig. 167); sometimes they are elongated like a horn, as in the Columbine (Fig. 168); sometimes they are helmet-shaped, as in the Aconite (Fig. 169). Petals, like leaves, are either entire or indented. They present, like them, a sort of skeleton, if one may give that name to vascular and slender ramifications, which can only be perceived clearly in some cases by placing the petal between the eye and the light, so as to look at them as at a transparency.

The veins determine the shape assumed by the petal. Figs. 170, 171, and 172 give an idea of the three principal forms for the

i\ i ey

Fig. 170—Petal of Wallflower. Fig, 171.—Petal of Winter Fig. 172.—Cerastium precox. Hellebore, distribution of the veins. We know that in the Wallflower (Fig: 170) the petal is elongated at its lower part by a slender portion called the claw (wnguis), the larger part of the petal taking, in this latter case, the name of the limb. The petals of the Cerastwm precox (Fig. 172) and Winter Hellebore (Fig. 171) have no claw, and, as we see, one limb only.

The number of petals in a corolla vary much; they are sometimes very numerous, and are then arranged in a spiral form; ut they are oftener few in number, and are then arranged in one whorl. In the Cactus the petals are extremely numerous, and arranged in a spiral, continuous with that of the sepals. In the Geranium (Fig. 173), Violet, and Gilliflower (Fig. 174), there are only five petals arranged in a whorl.

Just as the calyx may be monosepalous, or polysepalous, so the corolla is monopetalous or polypetalous. The flower of the

Fig. 173.—Flower of Geranium. Fig. 174.—F1 f Gillifl

Geranium (Fig. 173), and of the Rose, and Pink, have their petals perfectly distinct, so that one can be detached without interfering with the others. On the contrary, the Lilac “ (Fig. 175), the Primrose, and the Belladonna, have \ their petals united together at their edges, so that one cannot pull off a petal without breaking in on an adjacent one. When a flower begins to expand, the petals are always free. The transformation of a corolla, at first monopetalous, into a polypetalous corolla, takes,.115 sronopela-place in the bud, just as we have already shown to!uscoroliaof Lilac. be the case with the calyx; that is, the free extremities of the petals are supported and united in one whole by a common and continuous membrane.

We have remarked, that the sepals are developed on the receptacle in succession, whilst the petals appear, on the contrary, simultaneously. This fact may help us to resolve a problem, which much occupied the attention of the older botanists.

In the Lily (Fig. 176), for instance, the floral envelopes are composed. of six divisions, which are white, and of a delicate tissue, analogous to petals. Do the whole of these divisions constitute a - corolla? By no means. Without mentioning the differences of shape, size, structure, and position, which could not escape the eyes of an attentive observer, we can show that the pieces of the external whorl of the Lily are developed in succession, like sepals,

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