Part 12

The Liliaceæ are a very numerous tribe, including the Lilies, Hyacinths, and Tulips, the Onion, Garlic, Asparagus, the Cape Aloe, Yucca, and many others; they are for the most part bulbous plants, having simple leaves enclosing the stem. The Palms are included in this order; they are among the tallest and most graceful of the vegetable tribes, and in the countries where they abound are applied to almost every purpose that can be enumerated.

7. AMARYLLIDACEÆ (Narcissus kind).

The Amaryllidaceæ are the Narcissus tribe, including also the Agave, or American Aloe, and the Snow-drop. The greater number of species belonging to this order are natives of the Cape of Good Hope, some of these are poisonous; the juice of the Cape Blood-flower (Hæmanthus Toxicarius) is used by the Hottentots to poison their arrows with.

8. IRIDACEÆ (Crocus tribe).

The Iridaceæ include the Crocus (Crocus sativa), the Corn-flag (Gladeolus communis), and the Blue-flag (Iris Germanica); the bulb of the Iris Florentina, is dried and used for various purposes, it has a scent resembling violets and is sold at druggists' shops by the name of orris-root, a corruption of iris-root.

9. ORCHIDACEÆ (Orchids).

The family of the Orchis. Dr. Baird, in describing them, says:--"They are almost all herbaceous, a very few only being somewhat shrubby in their growth; some live in the ground, and besides the ordinary roots have bulbs or starch-bearing tubercles; others are what may be called pseudo-parasites, living attached to the bark of trees. These plants abound in the forests of tropical countries, where the climate is moist, and are generally known by the name of Epiphytes. The flowers vary very much in shape, form, and colour, and in many instances have a striking resemblance to insects, various birds, and animals, as Oncidium, in which the resemblance is to butterflies, &c.; Cychnoches, in which (in one species) the likeness is strikingly similar to a swan; Peristeria, one species of which is called the Sprito-Santo plant, of Panama, and in whose flower there is the likeness of a dove descending upon the lip, &c. A curious fact in this part of their history is, that in the same plant, on the same stem, and even on the same head of flowers, we find flowers so different in appearance that we might place them in different genera."

10. NAIADACEÆ (Naiads).

Water-plants, called "pond-weeds," and grow on both fresh and salt water. The marine species, Zostera marina, is dried and used for stuffing mattresses.

11. BUTOMACEÆ (Flowering Rushes).

Of this order the Butomas umbellatus, a sort of rush, producing very handsome pink flowers in umbels, growing in ditches and by the sides of rivers, is the most characteristic member.

12. ALISMACEÆ (Water Plantain).

The two chief members of this order are the Alisma Plantago or Water Plantain, which grows in ditches, having its flowers in the form of panicles, and the Sagittaria sagittæfolia or Arrowhead.

* * * * *

The third great natural family of plants are the Exogenæ. They comprise all the trees and shrubs of the temperate and colder regions, together with many of the flowering plants. They are characterised by certain peculiarities which can be at once recognised, such as the twisted and branched form of the stem, the possession of bark, leaves having the veins covering them running in all directions and forming a network, and the seeds containing two cotyledons; the wood, moreover, is deposited in rings (figs. 16, 17, 18, 19), one of which is formed every year, by the new wood being produced on the outside of the old, and between it and the bark. This deposition takes place as follows: after the rains of winter and early spring have well saturated the earth with moisture, and the warmth of spring has begun to penetrate to the roots of the plants, a development of the points of each fibrile or radicle takes place, forming new spongioles; these, being formed of new porous cellular tissue, begin to absorb (by endosmose) the moisture of the earth, which entering at all these thousands of minute spongioles at once, collects and rises in the vessels of the trunk and branches, and arriving at the vessels forming a plexis on the surface of every leaf, begins to be changed by the action of the sun's rays, absorbing carbon and giving out oxygen from the carbonic acid always contained in the air. The sap which has thus risen is the juice of the earth in which the plant grows, containing several earthy salts and vegetable extract drawn from the manure or decaying vegetation contained in the mould, together with carbonic acid dissolved in the fluid; this carbonic acid is changed by the sun's rays as well as that which was contained in the air, and the carbon uniting with the watery part of the sap, forms the green substance before alluded to, called chlorophyll, which is the green colouring matter of all plants, and is the basis of the wood. The altered sap descends between the wood and the bark, and forms a deposit gradually, which at the end of the year is a complete ring of wood surrounding the wood of former years. This circulation of juices continues through the summer, until, the cold weather coming on and the light being diminished, the sap neither rises nor is the leaf nourished by it, when it decays and falls off.

The age of exogenous wood can be ascertained--where the centre has not decayed--by counting the rings, one only being deposited every year; and it is truly astonishing to find that some trees will continue to live and flourish for several thousand years! There does not, in truth, appear to be any limit assigned to the life of an exogenous tree if it escape accidents; for, although decay inevitably attacks the heartwood, and a cavity is the result, yet, the new wood continuing to be deposited on the outer part, the vitality of the tree is kept up, and its size continues to increase.

The Baobab or Monkey Bread-fruit trees, growing at the mouths of the Senegal, have been estimated by Adinson to be upwards of six thousand years old, and are, in all probability, the oldest relics of organic life existing at the present time. The cedars of Lebanon are supposed to have existed longer than the records of history. The Yew at Braburn, in Kent, is at least three thousand years old; and that of Fortingal nearly as much.

Dr. Livingstone, describing the Mowana or Baobab tree (fig. 20), thus comments upon its power of withstanding injury:--

"No external injury, not even a fire, can destroy this tree from without, nor can any injury be done from within, as it is quite common to find it hollow, and I have seen one in which twenty or thirty men could lie down and sleep as in a hut. Nor does cutting down exterminate it, for I saw instances in Angola in which it continued to grow in length, after it was lying on the ground. Those trees, called exogenous, grow by means of successive layers on the outside; the inside may be dead, or even removed altogether, without affecting the life of the tree; this is the case with most of the trees of our climate. The other class is called endogenous, and increases by layers applied to the inside, and when the hollow of the tree is full, the growth is stopped, and the tree must die. Any injury is felt most severely by the first class on the bark, by the second on the inside, while the inside of the exogenous may be removed, or the outside of the endogenous may be cut, without stopping the growth in the least. The Mowana possesses the power of both. The reason is, that each of the laminæ possesses its own independent vitality; in fact, the Baobab is rather a gigantic bulb run up to seed than a tree. The roots, which may often be observed extending along the surface of the ground forty or fifty yards from the trunk, also retain their vitality after the tree is laid low, and the Portuguese now know that the best way to treat them is to let them alone, for they occupy much more room when cut down than when growing."

On examining the wood of the exogenæ, it will be found that in the very centre is a small column of cellular tissue, called the pith, and that from this, fine layers of the same substance radiate towards the circumference. These are called the medullary rays, or silver-grain; they form an exterior layer or ring of cellular substance on the outside of the wood, which is called the cambium. The lightness of wood is owing to its porosity, and, on examining a transverse section under the microscope (figs. 17 and 19), it will be seen how little of real space is occupied in wood by solid substance. The spaces between the wall-work of woody matter in the tree are all filled with sap, and hence it is that "green wood" is so much heavier than that which is well seasoned. It is its lightness and strength, together with the ease with which it can be cut and fashioned, which renders wood so exceedingly useful; but its inflammability and liability to decay are great barriers to its more general use.

The leaves of the exogenæ have their veins always in the form of a network, and not running parallel with each other, as in the endogenæ (fig. 21).

Of the three divisions of the vegetable kingdom, the exogenæ alone furnish building timber, properly so called, and it is doubtful whether nature has supplied a more generally applicable substance than wood; being a bad conductor, it can be handled in the coldest weather, which metal cannot, and, being easily cut or split, can be fashioned into almost any form.

The woods mostly in use for general purposes are the different kinds of pine, as American Pine, Norway Pine, yellow and white Deal, Mahogany, Oak, Beech, Elm, Ash, and Maple. In the "Penny Cyclopædia," under the article "Wood," is the following description of the different kinds used by cabinet-makers, &c.:--

"The woods that are used by the cabinet-maker for furniture of a more delicate kind are called 'fancy woods.' The use of these has become much more general since the introduction of the art of veneering, and now that this is done by machinery instead of by hand, a number of woods are used for furniture and other purposes, which, on account of their scarcity, could have been formerly used only to a very limited extent. The most common of the fancy woods, and that which is most used by cabinet-makers, is Mahogany. This wood is the produce of the 'Swienteria Mahogani.'

"Next in point of importance and use to Mahogany, is Rosewood. This wood obtains its name from its fragrance, and is the produce of a mimosa from the forests of Brazil; in veneering it affords about eight plates to the inch.

"King-wood is a beautiful wood much in use, brought from Brazil in logs four feet long and about five inches wide, and is used only for delicate articles; it is said to be the produce of a species of Baphia, a genus of Leguminous plants.

"Beef-wood is a very heavy wood of a pale red colour, and is brought from New Holland in logs nine feet long and thirteen or fourteen inches wide; the tree from which this is obtained is unknown to botanists, as well as most of those producing the fancy woods of commerce.

"Tulip-wood is brought into the market in very small pieces, not more than four feet long and five inches in diameter, so that probably it is the production of a shrub; it is clouded with red and yellow colours, and is used for bordering and for making small articles, such as caddies and work-boxes.

"Zebra-wood is probably the production of a large tree, as it is cheap enough to be made into tables, pianofortes, &c.; it is coloured brown on a white ground and clouded with black.

"Satin-wood is of a brilliant yellow colour with delicate glowing shades. It is the produce of a plant called Chloroxylon Swienteria, a native of India; it is one of the trees that yield the wood-oil of India, and belongs to the natural order Cedrelaceæ, the same order in which the mahogany is placed; it is found in the market in logs two feet wide and seven or eight feet long.

"Sandal-wood is the produce of a species of Sandoricum belonging to the family Meliaceæ; the wood is of a light brown colour with golden-coloured waves.

"Ebony and Iron-wood are the names given to some very hard woods, the produce of the natural order Ebenaceæ. These woods are mostly brought from India, although some of the species are found in Europe and America.

"There are several other woods occasionally used amongst cabinet-makers, of which little is known, either with regard to the places they come from, or the trees to which they belong. Canary-wood has a yellow colour; Purple-wood has a purple colour, without veins; Snake-wood is of a deep colour with black shades; Calander-wood is a handsome cheap wood taking a high polish, and is brought from Ceylon.

"Other woods are named after the places they come from, as Coromandel-wood, Amboyna-wood, &c."

Woods are largely used as dye-stuffs; the chief of these is log-wood, which has a deep red colour, is very heavy and solid, and yields a great deal of red colouring matter. It is very astringent, and contains tannic and gallic acids, from which properties it produces a deep black colour when mixed with any of the salts of iron; from this peculiarity it is very valuable as a black dye, but the black dye so extensively used for dyeing cloth, is, for the most part, made from galls, or "nut-galls," as they are sometimes called. These are hard round substances found growing on many species of oak, chiefly the "Quercus infectoria," and the best are brought from Aleppo; they are diseased growths produced by a little insect, called the "Cynips Quercus," which deposits its eggs under the epidermis of the leaf, and the juice collects and forms the gall (fig. 22), from the interior of which the larva eats its way out; thus it will be found that every gall must have a little round hole in it, whence the larva of the cynips has issued.

The root of the Madder plant (Rubia tinctorum) produces the most beautiful and permanent of our red dyes, and the cochineal insect (Coccus cacti) obtains its colour from feeding upon the cactus.

A useful and very permanent blue dye is obtained from Indigo, a kind of extract from the plant "Indigofera," growing in India and other places, and many other members of the vegetable kingdom yield dyes and colours used in the arts.

Amongst the various and almost endless purposes to which wood is applied, that of serving as a material to engrave on and print from must not be omitted. The wood used for this purpose is that of the box-tree (Buxus sempervirens), which furnishes a close, even-grained, hard wood, admirably suited to the purpose; and the cultivation and perfecting of this most admirable art, has produced an improvement in book-illustrating which can hardly be sufficiently appreciated.

Wood must have supplied one of the earliest materials with which to erect buildings; the Grecian styles of architecture, beyond doubt, were derived from imitating in stone those structures first made of wood. All the largest members of the vegetable kingdom belong to this division; and indeed the same may be said of size which has been said of age, namely, that there is no limit except from accidental circumstances.

In the Crystal Palace at Sydenham is a most wonderful and gigantic specimen of the Wellingtonia Gigantea (fig. 23), one of the class of trees called coniferous, and belonging to the exogens, the bark of which has been stripped off in portions at the place where it grew, each of which being numbered, has enabled them to be re-adjusted in their original places, the result of which is, the whole bark of this most magnificent tree appears as if growing on the timber. It measures 31 feet across at the base, and 93 feet in circumference; the original tree was 363 feet in height, its present height is 116 feet, and the bark is 18 inches thick. The Norfolk Island Pine (Araucaria excelsa) sometimes grows to 300 feet in height, and Humboldt, describing a specimen of the Pinus Trigona, says, "This gigantic fir was measured with great care; the girth of the stem at 6-1/4 feet above the ground was often 38 to 45 feet; one stem was 300 feet high, and without branches for the first 192 feet."

As the exogens grow by the addition of woody matter to their circumference, of course the older the tree (other conditions being equal) the larger will be the trunk, but as the new wood is added to the outside, the centre loses its vitality and is liable to the attacks of both animal and vegetable parasites, and is therefore constantly found either decayed or totally destoyed; this is not, however, invariably the case, and many instances are found of wood of a great age remaining sound in the centre. At St. Nicholas in Lorraine is exhibited a plank of walnut wood made into a dining-table which is twenty-five feet wide. Besides timber for various useful purposes, this division of the vegetable kingdom furnishes us with both cotton and linen for clothing, and many of the dye-stuffs for ornamenting such clothing, also with many articles of food (although not so prolific in this respect as the Endogenæ), the potato, most green vegetables, as cabbages, lettuces, are exogenous, together with such roots as carrots, parsnips, &c.

To this class of plants belong many of the most beautiful flowers, and all our fruit-trees, not the least important of which is the fig-tree, although the fig can hardly be called a fruit in the strict sense of the word, being a consolidated mass of flowers within a receptacle. The figs of commerce are produced from the Ficus carica, the fruit being dried in the sun; they form a considerable article of commerce. The celebrated Banyan tree (Ficus indica, fig. 24) is one of the fig tribe, it throws down branches (as do many others of this tribe) which take root in the earth and form fresh stems, so that one of the banyan trees with its off-shoots will cover a space of ground sufficient to shelter a regiment of cavalry, and many of the fig tribe, especially the sycamore (Ficus sycamorus), are planted for the sake of the shelter they supply by their broad crowns of leaves; another of the fig trees (Ficus elastica) supplies a great part of the India-rubber of commerce.

De Candolle divides the class of exogens into four sub-classes according to the arrangement of their flowers &c.; they are as follows:--

1. THALAMIFLORÆ, the flowers of which are furnished with both calyx and corolla, the corolla having distinct petals, and the stamens hypogynous, that is, growing immediately from below the pistil.

2. CALYCIFLORÆ, having flowers with both calyx and corolla, the corolla divided into distinct petals, but the stamens always Perigynous, that is, growing upon the sides of the calyx.

3. COROLLIFLORÆ, having flowers with both corolla and calyx, the former having its petals united.

4. MONOCHLAMYDEÆ, flowers without corolla and often without a calyx.

These four sub-classes have been divided into orders as follows:--

ORDERS OF THALAMIFLORÆ.

1. NYMPHACEÆ (Nymphæa alba) White Water-Lily. (Nuphar luteum) Yellow Water-Lily.

This order contains water plants of great beauty, they grow in the mud at the bottom of the water, sending up long flower- and leaf-stalks so that the flowers may blossom in the air and the leaves float on the surface; the leaves are generally round and turned up slightly at the edges. The "Victoria Regia" is a magnificent specimen of this order; it originally came from Brazil, and has flowers a foot wide, leaves four or five feet across, and is sufficiently buoyant, it is said, to bear the weight of a child. The Lotus of the Nile, the blossom of which so frequently occurs on the carvings of the Egyptians as an offering to Isis, is another member of this order.

2. PAPAVERACEÆ (Papaver somniferum) White Poppy. (Papaver Rhoeas) Red Poppy.

Opium is prepared from the unripe capsules of the White Poppy, it is chiefly cultivated for this purpose in India and Turkey. The Chinese are the great consumers of opium, it being a common habit with them both to eat and smoke it. Opium is made by collecting the juice in the morning which has exuded from incisions made in the capsules over night; those employed for this purpose use a small knife with several blades and go round the plantations scarifying the capsules in the evening, and the juice which issues and forms a thick concrete matter, is scraped off, beaten up, and dried in round lumps. About £2,000,000 worth are exported from India annually.

3. RANUNCULACEÆ (Anemone coronaria) Garden Anemone. (Aconitum Napellus) Monk's-hood. (Ranunculus acris) Butter-cup.

Besides the above examples, there are many beautiful flowers belonging to this order, as the Clematis and Peony. Members of this order are for the most part poisonous, and some of them, as Monk's-hood and Hellebore, are violently so, while even the Butter-cup is to a certain extent acrid.

4. FUMARIACEÆ (Fumaria officinalis) Fumitory.

This order contains no plant of any importance. The common Fumitory derives its name from the supposed resemblance of the odour of its flowers to smoke.

5. BRASSICACEÆ (Sinapis alba) White Mustard. (Nasturtium officinalis) Water Cress. (Brassica oleracea) Cabbage.

In this order are contained many of the useful occupants of our kitchen gardens, the Cabbage, Turnip, Cauliflower, Radish, and many more; they have nearly all a pungent taste, and some, as the Rape, yield seed producing much oil. The Water Cress is grown near London in square pools, into which some neighbouring stream is turned. These pools are arranged side by side, and those who gather the plants lie down on a plank of wood placed across. Enormous quantities are thus supplied to the London markets.

6. CISTACEÆ (Helianthemum Vulgare) Helianthemum.

These plants are for the most part evergreens; the Yellow Cistus is our most familiar example of the order. In Turkey the Rock-roses are much cultivated, they exhale a gum having a highly aromatic odour, which is there used as a perfume.

7. BERBERIDACEÆ (Berberis vulgaris) Common Berberry.

The Berberry is commonly found in our hedgerows, and its fruit is sometimes eaten; in Italy it grows to a good-sized tree. It is remarkable as furnishing an example of vegetable motion, from the irritability of its stamens, which if touched will bend forward in a curved position, and touch the stigma with the anther, and after remaining a short time in that position the stamens recover their natural form.

8. VIOLACEÆ (Viola odorata) Sweet Violet. (Viola tricolor) Heart's-ease.