3d. Cup shaped (Cyathiformis, from cyathus, a drinking cup), differing from funnel shaped in having its tube, and of course its border, less spreading; and from bell form, in not having its tube appear as if scooped out at the base (Fig. 52). Fig. 53. 4th. Salver form (hypocrateriformis, from the Greek krater, an ancient drinking glass, called a Salver). Having a flat spreading border, proceeding from the top of a tube (Fig. 53). Fig. 54. 5th. Wheel form (rotata, from rota, a wheel), having a short border without any tube, or with a very short one (Fig. 54). Fig. 55. 6th. Labiate (from labia, lips), consists of two parts, resembling the lips of a horse, or other animal. Labiate corollas are said to be personate,* having the throat closed, or ringent, with the throat open. have here a labiate corolla of the ringent kind (Fig. 55). * From persona, a mask. + From ringo, to grin or gape. Cup-shaped-Salver-form-Wheel-form-Labiate, how divided? You Fig.56. Different forms of Polypetalous Corollas. 1st. Cruciform (from crux, a cross), consisting of four petals of equal size, spreading out in the form of a cross, as the radish, cabbage, &c. (Fig. 56). Fig. 57. 2d. Caryophyllous, having five single petals, each terminating in a long claw, enclosed in a tubular calyx, as the pink, (Fig. 57). 3d. Liliaceous, a corolla with six petals, spreading gradually from the base, so as to exhibit a bell form appearance, as in the tulip and lily. 4th. Rosaceous, a corolla formed of roundish spreading petals, without claws, or with very short ones, as the rose and apple. 5th. Papilionaceous, a flower with a banner, two wings, and a keel: the name is derived from the word papilio, a butterfly, on account of a supposed resemblance in form, as the pea blossom (Fig. 58).* If a corolla is not in its form like any of those we have descri. bed, it is said to be anomalous.t [† For this note, vide page 98.] *It is proper here to observe two important facts connected with the descriptions of plants, which are made by references to natural and artificial forms. "1st. A certain number of forms were assumed by Linnæus as standards for Forms of polypetalous corollas-Cruciform-Caryophyllous-Liliaceous— Rosaceous-Papilionaceous-Anomalous corollas. Odour of Flowers. The odour of flowers has its origin in the volatile oils, elaborated by the corolla: its production results from causes both external and internal, but equally beyond our observation. Temperature renders the odours of flowers more or less sensible; if the heat is powerful, it dissipates the volatile oils more rapidly than they are renewed; if the heat is very feeble, the volatile oils remain concentrated in the little cells where they were elaborated; in both cases the flowers appear to possess but little odour. But if the heat is neither too great nor too little, the volatile oils exhale without being dissipated, forming a perfumed atmosphere around the flowers. You see now the reason, that when you walk in a flower garden in the morning, or towards evening, the flowers seem more fragrant, than in the middle of the day. The air being also more charged with humidity, is another cause of an increase of fragrance at those times; the moisture, by penetrating the delicate tissue of the corollas, expels the volatile oils. There are some exceptions to the laws just stated; for some flowers are only odorous during the night, and some others during the day. Some flowers exhale fetid odours, which attract such insects as are usually nourished by putrid animal substances. Many flowers exhale sweet odours; but however odours may differ, in the sensations which they produce, it is certain, they all have a stupifying, narcotic effect upon the nerves, and that it is dangerous to respire, even the most agreeable of them, in a concentrated state, for any great length of time. One important office of the corolla, is to secure those delicate and important organs which it encloses, the stamens and pistils, from all external injury, and to favour their developement. After the germ has become fertilized by the influence of the references; none of which are to be considered as perfect. But when any one of these forms is referred to, it is to be understood that it is nearer the true form of the organ under consideration, than any other of these standard forms. "2d. All standard forms are either drawn from well known natural bodies, or from artificial bodies, or implements known to the ancients. Some of the most common natural bodies are the egg, lips of animals, the throat, head, knee, the heart, the kidneys, the hand, bird's feet, spur, feather, tooth, hair, bristles, silk, down, eye lashes, veins, nerves, wings, ears, claws, &c. Some of the most common artificial bodies or implements, are a spike, spindle, circle, oval, lance, line, awl, arrow, halbert, viol, lyre, saw, shield, cross, sabre, needle, bell, keel, club, cone, leather, cup, fork, urn, wheel, &c.-Eaton. + Anomalous is derived from two Greek words, a, without, and nomos, law; it signifies without law or rule. Origin of the odour of flowers-Odour affected by temperature-Odour affected by moisture-Odours sometimes disagreeable-Dangerous of respiration for a long time-Uses of the corolla. pollen, the corolla fades away, and either falls off or remains withered upon the stalk; the juices which nourished it then go to the germ, to assist in its growth and enable it to become a perfect fruit. Another use of the corolla seems to be, to furnish a resting place for insects in search of honey. The corolla is supposed by Darwin to answer the same purpose to the stamens and pistils, as the lungs in the animal system; each petal being furnished with an artery which conveys the vegetable blood to its extremities, exposing it to the light and air under a delicate moist membrane; this vegetable blood, according to his theory, is then collected and returned in correspondent veins, for the sustenance of the anthers and stigmas, and for the purpose of secreting honey. Bernardin de Saint Pierre,* author of the interesting story of Paul and Virginia, thinks the corolla is intended to collect the rays of the sun, and to reflect them upon the stamens and pistils which are placed in the centre. It After all our enquiries into the uses of the corolla, we are obliged to acknowledge that it appears not as important, in the economy of vegetation, as many less showy organs. seems in reality designed chiefly to beautify and enliven creation, by the variety and elegance of its forms, the brilliancy of its colouring, and the sweetness of its perfume. Nectary. In many flowers there is an organ called the nectary, which secretes a peculiar fluid, the honey of the plant; this fluid constitutes the principal food of bees, and various other species of insects. Linnæus thought the nectary to be separate from the corolla; and every part of the flower which was not stamen, pistil, calyx or corolla, he called by this name: his remarks on this subject have given rise to more severe criticisms than almost any other part of his system. It is thought he applied the term nectary too extensively, and in too vague a manner. We cannot assert that the nectary is a separate organ from the corolla, because it often makes a part of it; although sometimes it is entirely separate. The nectary seems not to be confined to any particular part of the flower. Sometimes it is a mere cavity, as in the lily. *This ingenious author remarks, that man seems the only animal sensible to the sweet impressions, made by the colour and odour of plants upon the senses; but we think he has asserted too much. Do not the brute creation seem to enjoy, by the sense of smelling, the freshness of the verdant fields? But man is very apt to say, "See all things for my use." Nectary-Its use--] Fig. 59. The crown imperial (Fritillaria Impe rialis), exhibits in the claw of each of its petals, a nectary of this kind; each one being filled with a sweet liquid, the secretion of the flower. If these drops are removed, others immediately take their place. You have here a representation (Fig. 59) of the crown imperial; its petals appear cut off near the base, in order to show the six nectariferous glands at the base of each. In the ranunculus, the nectary is a production of the corolla in the form of a scale; in the violet a process of the same, in the form of a horn or spur. In the columbine, the nectary is a separate organ from the petals in the form of a horn. In the monks-hood, one of the petals being concave, conceals the nectaries; they are therefore said to be hooded. In monopetalous corollas, the tube is supposed to answer the purpose of a nectary in secreting the honey. In the honeysuckle we find at the bottom of the tube, a quantity of nectariferous liquid, yet there is no appearance of any gland or organ, by which it could have been secreted, unless we suppose the tube to have performed this office. With respect to the purpose for which honey is secreted by the nectary and other parts of the flower, there seems, among authors, to be some difference of opinion. Darwin supposes this to be the food with which the stamens and pistils are nourished, or the unripe seeds perfected. Smith asserts, that the only use of honey with respect to the plant, is to tempt insects, which in procuring it, scatter the dust of the anthers, and fertil ize the flower, and even carry the pollen from the barren to the fertile blossoms; this is particularly the case in the fig-tree. Although in the case of plants whose stamens and pistils are on separate flowers, we see this advantage arising from the fact of insects being attracted by the honey, yet since the greater number of plants do not need this assistance in carrying their pollen to the stigmas, we cannot agree with Smith that the only use of honey is to tempt insects. With respect to the use of honey in the vegetable system, it seems difficult to determine; some imagine that it especially contributes to the perfection of the stamens; but plants without appearing to secrete honey, have perfect stamens. One thing Nectary of the crown imperial-Different forms of nectaries-Opinions of different writers respecting their use-Honey. |