Chapter I (2)

The genus Polygala is well known from the very handsome greenhouse plants which it contains. The flowers at first sight appear to resemble those of the Sweet Pea, having two wings like a standard, and a sort of keel; their construction is, however, very curious, and so complicated, as to be very difficult either to describe or to understand. The calyx is said by modern botanists to consist of five sepals, three of which are green and two lilac, these last being the part that resembles the standard of the Sweet Pea. The corolla is also said to consist of five petals, two of which stand erect, and the other three grow together to form the keel. The latter have their upper part cut into a kind of crest, like that of the Mignonette. Below the crest, the united petals form a kind of hood, under which are arranged the eight stamens, four on each side. The stamens themselves are as remarkable as the other parts of the flower; the filaments grow together into a thin kind of leaf, and each anther has but one cell, and opens by a pore at the apex. The pistil is also very curiously formed, as the style and stigma have the appearance of a gaping monopetalous corolla. The fruit is a flat two-celled capsule, which, when ripe, opens by two lips, separating from each other, and showing a seed within each cell. Even the seeds are not like other seeds, for each has a large white protuberance at one end, called a corancula.

ORDER XXIII. TREMANDREÆ.

Slender New Holland shrubs, with the habit of Heaths, rarely met with in British gardens.

ORDER XXIV. PITTOSPOREÆ.—THE PITTOSPORUM TRIBE.

The principal genera included in this order are Pittosporum, Billardiera and Sollya, all resinous shrubs, with alternate leaves without stipules, and the sepals and petals, each five in number, and laid over each other like scales in the bud. The seeds are numerous, and immersed in fibrous pulp. The commonest species of Pittosporum is _P. Tobira_, a native of China, easily known by its thick leathery leaves, the midribs of which are strongly marked, and whitish. The flowers are erect, and produced in cymes or heads; and the petals are united into a tube with a spreading limb. The capsule is one-celled, and two or three valved, with an imperfect dissepiment in the centre of each valve; and the seeds are numerous, and buried in a resinous fibrous pulp. The Billardieras are generally climbing shrubs, with pale greenish bell-shaped, and almost erect flowers, which are produced singly or in pairs, and which have the tips of their petals turned back. The fruit is a fleshy berry, with a shining skin of a deep blue, and it is called the Apple Berry in Australia, of which country the species are natives. This fruit is said to be eaten in Australia, but it seems difficult to imagine how this can be the case; as though the outer part of the berry is of a soft spongy nature, it is dry and insipid; and there is no internal pulp, for the seeds lie loose in the cells. In _Sollya heterophylla_ the flowers are drooping, on long and very slender pedicels, and they are produced in cymes. The corolla is campanulate, with the tips of the petals not recurved, and the anthers are much shorter than in Billardiera. The fruit is a soft fleshy berry, divided into two cells, each containing two rows of seeds immersed in pulp, and when cut open, it smells strongly of turpentine. The plant generally called _Sollya linearis_ has a dry and leathery pericardium; and for this reason and on account of the spreading of its anthers, it was placed by Mr. Cunningham in a new genus, which he called _Cheiranthera._

ORDER XXV. FRANKENIACEÆ.—THE FRANKENIA TRIBE.

The genus Frankenia consists principally of the British weeds called Sea Heath; and the other genera included in the order are seldom seen in British gardens, from the seeds which have been imported seldom arriving in a state fit for vegetation.

ORDER XXVI.—CARYOPHYLLACEÆ—THE CARNATION TRIBE.

The plants belonging to this order have so strong a family likeness to each other as to be easily recognised; and they are all distinguished botanically by the swollen joints of their stems, and their opposite undivided leaves, which are generally connate, that is united, and sheathing the stem. The order is divided into two sections, viz.: Sileneæ, in which the sepals are united into a tube, and which section includes the genera Silene, Dianthus, Saponaria, Lychnis, and Agrostemma; and Alsineæ, in which the sepals are either quite distinct, or only slightly cohering at the base, and which includes Stellaria, Arenaria, Cerastium, Spergula, and several other British weeds. The Chickweed was called by Linnæus _Alsine media_, but the genus Alsine is now united to Stellaria.

The Wild or Clove Carnation (_Dianthus Caryophyllus_), which may be considered the type of the order, has an erect stem, swollen at the joints, with connate leaves, (see _a_ in _fig._ 118). The flower, when single, consists of five petals, each with a very long narrow claw (_b_), and a rather broad limb or blade (_c_) serrated at the edge. The calyx (_f_) is tubular, with five vandyked teeth, which are in fact the tips of five sepals, into which the tube of the calyx may be easily divided with a pin. The tubular form of the calyx is admirably contrived to support the long claws of the petals, and to keep them in their proper places; particularly when the flowers are double, as the weight of the petals in that case frequently bursts the tube of the calyx. Every one fond of pinks and carnations must have observed the miserable appearance of the flower when thus deprived of its natural support; and to prevent the premature destruction of prize-flowers by this misfortune, professed florists sometimes slip a curiously-cut piece of card-board over the bud, which remains on after the expansion of the flower, and prevents the petals from falling out of place. Some florists tie the calyx round with thread, instead of using a pasteboard ring, which answers the same purpose. At the base of the calyx are two, four, or six leafy appendages (_g_), resembling bracts, which are called the calycine scales. These imbricated scales are, however, only found in the genus Dianthus. There are ten stamens (_d_) unequal in height, but none of them longer than the ovary round which they are placed. The ovary and the stamens are concealed in the cup of the flower, but the former is furnished with two styles, terminating in two long stigmas (_e_), which project beyond the flower, and which, when magnified, appear delicately fringed.

The genus Dianthus includes the Carnation, the Pink (_Dianthus plumarius_), the Chinese Pink (_D. sinensis_), the Sweet William (_D. barbatus_), and many ornamental flowers. Of these the Sweet William has the claws of its petals bearded; the flowers are produced in bundles or fascicles; and the calycine scales are so numerous and awl-shaped, that they give a bristly appearance to the flowers. The different species of Soap-wort (_Saponaria_) differ from Dianthus, in having no calycine scales; and this is also the case with the berry-bearing Campion (_Cucubalus baccifer_), the fruit of which is a fleshy capsule or berry, which finally becomes black, and has a singular appearance in the centre of the cup-like calyx, which remains on till the fruit is ripe. The flower of this plant is white, and the petals have a two-cleft limb. All the numerous species of Catchfly (_Silene_) are also without calycine scales, and the petals are generally deeply two-cleft; but they are distinguished by having a crown of petal-like scales in the throat of the corolla. There are also three styles instead of two; and the capsules are three-celled at the base, ending in six teeth at the top. The species have frequently a glutinous frothy moisture on the stem, in which flies sometimes become entangled, and hence the English name of the genus. One species, the Bladder Campion (_S. inflata_), has been used as food, and its young shoots, when boiled and sent to table like Asparagus, are said to have the flavour of green peas. The different species of Lychnis and Agrostemma resemble Silene closely in every respect, except in the styles, which are five, instead of three; these two genera, Viscaria, and Githago, differ very slightly from each other; and several of the species are known by different names: thus Ragged Robin (_Lychnis flos cuculi_) is made by some botanists an Agrostemma; the Corn-cockle is sometimes called _Githago segetum_, and sometimes _Agrostemma Githago_; the common Rose Campion is called sometimes Lychnis, and sometimes Agrostemma; and the Rock Lychnis, or Red German Catchfly, sometimes _Lychnis Viscaria_, and sometimes _Viscaria vulgaris_.

ORDER XXVII.—LINACEÆ.—THE FLAX TRIBE.

The order Linaceæ is a very small one; and, indeed, it consists principally of the genus Linum. The Flax was formerly included in the Caryophyllaceæ, which it resembles in having five petals, five sepals, and five stamens; but it also resembles the Mallow in its capsules, and in its stamens growing together at the base; and the Cistus in its persistent calyx, and the disposition of its sepals. These links, which connect one order with another, and make them appear alike but not the same, form, I think, one of the most interesting parts of the Natural System. We are led on from one gradation to another, by scarcely perceptible shades of difference through the vegetable kingdom; and, indeed, through the whole system of creation: the beautiful harmony, and unity of design, visible throughout, bearing the strong impress of the Divinity whose power has made the whole.

The common Flax (_Linum usitatissimum_), though in its appearance only an insignificant weed, is a plant of great benefit to man. The fibres of the stem are used to make linen, and the seeds (linseed) are crushed for oil. The flowers are blue, and have five regularly-shaped petals, which are twisted in the bud; and a distinct calyx of five pointed sepals, two of which grow from a little below the others, as in the Gum Cistus; and, as in that plant, the calyx remains on till the seeds are ripe. There are five stamens, the filaments of which grow together slightly at the base, and there are five little points like filaments without anthers, rising between the stamens. The petals are connected with the ring formed by the united filaments, and sometimes the petals themselves grow slightly together at the base. The capsule consists of five two-celled carpels, grown together; each cell containing one seed, and each carpel terminating in a rather slender style, tipped with a ball-like stigma. When ripe, the capsule opens naturally, by dividing into ten valves, to discharge the seeds; which are flat and shining, with a large embryo. These seeds are called Linseed in the shops, from Linum, the botanical name of the plant; and, as is well known, they are not only used for various purposes, but oil is expressed from them. The stem of the common Flax, though it is only an annual, consists of woody fibre, like that of a tree in its young state; and it is this fibrous part that makes the yarn for thread, after it has been separated from the fleshy part, by steeping the stems for a long time in water. The perennial Flax (_Linum perenne_), which, as its name imports, lasts several years, differs in little else from the common kind, except that its sepals are obtuse, and its leaves are much smaller and narrower. Both these are natives of Britain. There are many other species, some of which have yellow flowers.

ORDER XXVIII.—MALVACEÆ.—THE MALLOW TRIBE.

FIG. 119.—THE FLOWER, STAMENS, AND PISTILS OF THE ALTHÆA FRUTEX.

All the plants belonging to Malvaceæ bear so much resemblance to each other, that this order may be considered a very natural one; and it is one very remarkable for the botanical construction of its flowers. In some respects it resembles Linaceæ, quite enough indeed to show clearly the chain by which they are so beautifully linked together; but in others, it differs so decidedly as to show how completely they are distinct. _Fig._ 119, which represents the flower and seed-vessel of the Althæa frutex (_Hibiscus syriacus_), will serve to show the chief peculiarities of this order. The calyx consists of five sepals, below which is an involucrum of six or seven leaflets, which have the appearance of a second calyx. The corolla is cup-shaped, and consists of five petals, which are close together at the base, and this is peculiar to the genus Hibiscus. The capsule is round and somewhat convex, being nearly in the shape of what is called a batch-cake, as shown at _c_; it consists of five carpels grown together, each containing many seeds; and when ripe, it bursts naturally into five valves, each of which has a dissepiment down the centre. The filaments grow together very curiously, inclosing the styles, and forming a column in the centre of the flower, which is the distinguishing mark of the Malvaceæ. Some of the stamens are shorter than others, and as part of each filament is detached, the anthers form the fringe-like border to the column, shown at _d_. The anthers are kidney-shaped and one-celled, and this is another of the characteristics of the order; but the styles are terminated by five ball-shaped stigmas, like those of the Linum. There are many kinds of Hibiscus; but perhaps the best known are: _H. rosa sinensis_, the species which is so often represented in Chinese drawings, and the petals of which are so astringent, that they are said to be used in China by the men to black their shoes, and by the women to dye their hair; and the Bladder Ketmia (_H. Trionum_), which takes its English name from its inflated capsule. All the plants belonging to the order Malvaceæ have a central column, round which are placed numerous carpels, which grow together and form a many-celled capsule; and they all have kidney-shaped, one-celled anthers. They have also always an involucrum below the calyx, but this involucrum differs in the different genera. In the genus Malva, the involucrum consists of three leaflets, which in the common Mallow (_Malva sylvestris_) are oblong. The petals are wedge-shaped, and they are what botanists call auricled; that is, they are set so far apart at the base that light can be seen through them. The stamens are all of nearly the same height, and they form a kind of bunch round the styles, which are pointed. The capsule consists of a circle of woolly-looking carpels growing close together, but so as to be easily detached with a pin, and each fitting into a little groove in the receptacle, in which they are placed. As the seeds ripen, the involucrum falls off, but the large loose-looking calyx remains on. There is only one seed in each carpel; but as there are generally eleven carpels in each capsule, each seed-vessel contains this number of seeds. The leaves are lobed and toothed; and the whole plant is covered with long hairs, which are disposed in little star-like tufts.

The genus Malope closely resembles the Mallow; except that the petals are not wedge-shaped, and that it has a still larger calyx, the long sepals of which shroud the capsule as the involucre of the filbert does the nut. The involucrum is composed of three broad, heart-shaped leaflets, which remain on till the seed is ripe. The petals are also not so even along the margin; and the carpels are so disposed as to form a cone-shaped capsule, instead of a flat one.

The genus Lavatera has the leaflets of the involucre joined to the middle, so as to form a kind of three-cornered saucer below the capsule; and the capsule itself is completely covered with a part of the receptacle, which is dilated, and curved down over it. Lastly, the genus Althæa, the Marsh Mallow, has the involucrum cleft into six or nine divisions, and the carpels united into a globular capsule. The Hollyhock (_A. rosea_) belongs to this genus. Many other genera might be mentioned, but these will suffice to give my readers a general idea of the order, and of the points of difference which distinguish one genus from another. Among the exotic plants belonging to the order is the cotton tree (_Gossypium herbaceum_), the cotton being the woolly matter which envelops the seeds in the capsule. All the Malvaceæ abound in mucilage, and they all have woody fibre in their stems.

ORDER XXIX.—BOMBACEÆ.—THE SILK COTTON TREE TRIBE.

This order is closely allied to Malvaceæ, and it differs principally in the tube formed by the stamens being divided into five bundles near the top. It includes the Baobab, or Monkey-bread (_Adansonia digitata_), said to be the largest tree in the world; the Screw tree (_Helicteres Isora_), so named from its curiously-twisted fruit; _Carolinia princeps_; the Silk Cotton tree (_Bombax Ceiba_); and the Hand-plant (_Cheirostemon platanoides_),—this is the Hand-plant so named from the lobes of its leaves resembling fingers,—all stove plants in Britain.

ORDER XXX.—BYTTNERIACEÆ.—THE BYTTNERIA TRIBE.

This order is divided into five sections, which some botanists make distinct orders. It is very nearly allied to Malvaceæ, but the anthers are two-celled. The principal genus in the first section (_Sterculieæ_) is Sterculia, which has several carpels distinct and arranged like a star: the species are trees with large handsome leaves which are articulated at the base, and axillary panicles or racemes of flowers. The second section (_Byttnerieæ_) contains among other plants _Theobroma Cacao_, from the fruit and seeds of which Cocoa and Chocolate are prepared. The third section (_Lasiopetaleæ_) is well known in England, by the pretty Australian shrubs included in the genera Thomasia and Lasiopetalum, the leaves of which have their under surface downy, and generally brown. The fourth section (_Hermannieæ_), and the sixth (_Wallichieæ_), contain no plant common in English gardens; and the fifth (_Dombeyaceæ_) is best known by _Astrapæa Wallichii_. The qualities of all the plants in this order are mucilaginous.

ORDER XXXI.—TILIACEÆ.—THE LINDEN TRIBE.

FIG. 120.—THE FLOWERS AND SEED-VESSEL OF THE COMMON LIME TREE.

The only genus belonging to the natural order Tiliaceæ which is easily to be procured in Britain is that of Tilia, the Lime trees. The common Lime (_Tilia europæa_) is generally a tall, well-formed tree, with rather broad leaves, which are heart-shaped at the base, tapering at the point, and serrated at the margin: they are also smooth on the outer surface, thin, and of a light and delicate texture; below there is a little tuft of hair at the angle of the veins. The flowers are produced in cymes or compound umbels (see _fig._ 120); and their main pedicel appears to spring from one long entire bract (_a_). The calyx is in five sepals, and it falls off before the corolla, which is composed of five pale yellow petals, which are very sweet-scented.

The stamens are numerous, and the filaments separate, bearing two-celled anthers, which burst by long slits. The ovary has only one style, the tip of which is cleft into five small stigmas; and it is divided into five cells, each containing one or two ovules. The fruit or capsule (_b_) is round, and has a leathery skin, covered with a soft down; and when ripe, the cells often become united so as to form one, with only one or two perfect seeds in the whole capsule, the other ovules proving abortive. The whole plant abounds in mucilage, and the sap when boiled affords sugar. The inner bark is so tough and fibrous, that it is used for making what are called bast mats: it being first rendered flexible by steeping it for a long time in water. The wood is of very fine texture, but soft and white, and it is thus admirably adapted for carving. The American Limes have a small scale at the base of each petal of the flower; but the other differences between the species are very slight.

ORDER XXXII.—ELÆOCARPÆ.—THE ELÆOCARPUS TRIBE.

East India shrubs and trees, little known in Britain. “The hard and wrinkled seeds of Elæocarpus are made into necklaces in the East Indies, and, set in gold, are sold in our shops.”—(_Hook._)

ORDER XXXII*.—DIPTEROCARPÆ.—THE CAMPHOR TREE TRIBE.

There are two kinds of Camphor, one produced by boiling the branches of a kind of laurel, and the other (the Camphor of Sumatra) is found in large pieces in the hollow parts of the branches of _Dryobalanops Camphora_, one of the species included in this order. None of these trees have been introduced into Britain.

ORDER XXXIII.—CHELONACEÆ, OR HUGONIACEÆ.

Small trees and shrubs, natives of the East Indies and Madagascar; only the genus Hugonia is known in Britain.

ORDER XXXIV.—TERNSTRŒMIACEÆ.—THE TERNSTRŒMIA TRIBE.

The principal plants in this order common in England are Gordonia, Stuartia, and Malachodendron. _Gordonia Lasianthus_, the Loblolly Bay, is a small evergreen tree, with white flowers, about the size of a rose. It is a native of America; and Stuartia and Malachodendron are beautiful low trees or shrubs, with large white flowers from the same country. The flowers have five large petals; the stamens are numerous, with the filaments growing together at the base, and attached to the petals; and there are five carpels more or less connected. Gordonia has its five sepals leathery, and covered with a silky down; its stamens almost in five distinct bundles, a five-celled capsule, and its seeds each furnished with a wing. Stuartia has a permanent calyx, five-cleft, but not parted into distinct sepals, with two bracts at the base, and a woody five-celled capsule, with seeds without wings; and Malachodendron (which was formerly called _Stuartia pentagynia_) has a calyx similar to that of Stuartia, but the edges of the petals are curiously crenulated, and there are five distinct carpels, each containing only one seed. Some botanists include the Camellia and the Tea in the order Ternstrœmiaceæ.

ORDER XXXV.—CAMELLIACEÆ.—THE CAMELLIA TRIBE.

There are two genera in this order, the Camellia and the Tea. The flower-bud of the Camellia is inclosed in a calyx of five, seven, or nine concave sepals, on the outside of which are several bracts, which remain on till the flower has expanded, but which are distinguished from the sepals by their dark brown colour. The sepals and the bracts are laid over one another like scales, and thus the flower lies encased in a complete coat of mail. The single flower is cup-shaped, with five, seven, or nine petals, which are sometimes joined together at the base. The stamens have long slender filaments, which either grow together at the base, or are separated into several bundles. The anthers are elliptical and versatile; that is, they are poised so lightly on the filament as to quiver with the slightest breeze. The ovary is of a conical shape, and it has three or five slender styles, ending in as many pointed stigmas, and growing together at the base. The capsule is three or five-celled; and when ripe it bursts into three or five valves, in the middle of each of which is a dissepiment, which, before the capsule opened, was attached to an axis or column in the centre. The seeds are large and few, and they are fixed to the central placenta. There is no albumen, but the embryo has two large, thick, oily cotyledons, which look as if they were jointed at the base. The leaves are leathery, dark-green and shining, and they are ovate in form, ending in a long point, and sharply serrated. The flowers spring from the axils of the leaves, and grow close to the stem without any footstalk; and the leaf-bud for the ensuing shoot grows beside the flower-bud.

I have above described the _Camellia japonica_, from which nearly all the Camellias in British gardens have sprung; but there are some other species. The finest of these is _C. reticulata_, which has very large, loose, widely-spreading flowers, of a remarkably rich crimson. The leaves are oblong, flat, and reticulately veined, being of a much finer texture than those of _C. japonica_. The ovary is two or four-celled, and it is covered with fine silky hairs. _C. maliflora_ is a very beautiful species with small semi-double flowers, coloured like an apple blossom. This Camellia is by some botanists thought to be a variety of _C. Sasanqua_, an elegant species with white fragrant flowers; but the ovary of the first is smooth, and that of the second covered with hairs, which most botanists consider a specific difference.

The Tea tree (_Thea viridis_) is very nearly allied to the Camellia; but there are many points of difference. The flower of the Tea tree has a footstalk; the calyx has only five sepals; the filaments of the stamens do not grow together; the capsules are three-seeded; and the dissepiments are formed by the edges of the valves being bent inwards, instead of being attached to a central axis. The leaves are also much longer than they are broad, and they are of a thinner texture and pale green; and the outside of the capsule, which is furrowed in the Camellia, is quite smooth in the Tea tree. It is said that both the green and the black Tea are made from the leaves of _Thea viridis_; but there is another species called _Thea Bohea_, which has smaller leaves, and is a more tender, and less vigorous-growing plant. The young leaves of _Camellia Sasanqua_, and some of the other Camellias, are also dried, and mixed with the tea. All these plants are natives of Japan and China, and require a slight protection in England during winter.

ORDER XXXVI.—OLACINEÆ.—THE OLAX TRIBE.

Exotic trees from the East and West Indies, little known in Britain. _Heistria coccinea_, a native of Martinique, is said to be the Partridge wood of the cabinet-makers.

ORDER XXXVII.—AURANTIACEÆ.—THE ORANGE TRIBE.

The natural order Aurantiaceæ contains fourteen genera; but the only one I think my readers will feel an interest in is the genus Citrus. This genus comprises, among several other species, _C. medica_, the Citron; _C. Limetta_, the sweet Lime; _C. Limonum_, the Lemon; _C. Paradisi_, the Forbidden fruit; _C. decumana_, the Shaddock; _C. Aurantium_, the Sweet Orange; and _C. vulgaris_, the Bitter or Seville Orange. to these may be added _C. nobilis_ the Mandarin Orange, the fruit of which is reddish, and which parts naturally from its rind, which is sweet, and may be eaten. All the species agree in having a tube-like calyx, scalloped into five short teeth, and a flower of generally five fleshy petals, (see _a_ in _fig._ 121), though the number occasionally varies from four to nine. These petals are elliptic in shape, concave, and always widely opened. In the centre of the flower are the stamens, varying from twenty (which is the ordinary number) to sixty; the anthers are two-lobed, and oblong, and the filaments are somewhat thickened at the base, and united there into several small bundles (_b_), but free above. The pistil has a somewhat globular ovary, with a cylindrical style, terminating in a stigma, which is slightly raised in the centre. The disk in which the stamens are inserted, forms a ring round the ovary. The fruit (_fig._ 122), which is considered by botanists to be a kind of berry, is in fact a seed-vessel with numerous cells, divided by dissepiments and a central placenta (_a_); the cells being the quarters of the Orange, the dissepiments the divisions between them, and the placenta the central pith. When the flower first expands, the ovary, if cut open and examined, will be found to be divided into several cells, each containing two rows of ovules. As in the preceding genera, however, many of these ovules become abortive; and as the cells fill gradually with cellular pulp, the seeds become detached from the placenta, and buried in it. The seeds themselves are very interesting; they are covered with a thick wrinkled skin, and they show distinctly the hilum (_c_ in _fig._ 121), the chalaza (_d_) and the raphe or connecting cord between them, parts which are seldom to be distinguished in seeds with the naked eye.

The leaves, calyx, and petals of the Orange, if held up to the light, appear covered with little dots. These dots are cells, covered with a transparent membrane, and filled with a kind of oil, which is exceedingly fragrant. The rind of the fruit is covered with similar cells, filled with a pungent oily liquid. The leaves are smooth and shining; and they are articulated; that is, they can be separated from the petiole or footstalk without lacerating them. In most of the species, the petioles are winged; that is, they are dilated into little leaves on each side (see _d_ in _fig._ 122). The different species vary chiefly in the number of stamens, the thickness of the rind, the shape of the fruit, and in the wings of the petioles. In the Citron these wings are wanting entirely, and instead of them there are spines in the axils of the leaves; there are generally forty stamens, and the rind of the fruit is very thick. In the sweet Lime, the petioles are slightly winged, and there are about thirty stamens; the fruit is small and round, with a slight protuberance at one end like that of the Lemon, and the pulp is sweet. In the Lemon the petioles are somewhat winged, the flowers have about thirty stamens; the fruit is oblong, with an acid pulp, and a thin rind. The Sweet Orange has winged petioles, about twenty stamens, and a fruit with a thin rind and sweet pulp; and the Seville Orange differs principally in having a thicker rind and bitter pulp. The China, St. Michael, and Malta Oranges, with many others, are all varieties of the Sweet Orange (_Citrus Aurantium_); and there are many other species, which I have not thought it necessary to describe.—All the species above-mentioned are natives of Asia, and most of them of China, but they have been so long cultivated in Europe and America, as to have become almost naturalised.

ORDER XXXVIII.—HYPERICINEÆ.—THE HYPERICUM TRIBE.

The genus Hypericum, or St. John’s Wort, agrees with the orange in having its leaves full of transparent cells; but these cells are filled with a yellow, resinous juice, resembling gamboge in its medicinal properties, and having a very disagreeable smell. There are five petals in the corolla; and the calyx consists of five sepals, which are unequal in size and shape, and joined together for only a short distance. Like the orange the filaments grow together at the base, in separate clusters or bundles; but in the Hypericum these clusters are so perfectly distinct, that the stamens may be readily separated into three or five bundles (according to the species), by slightly pulling them. The capsule is dry, and of a membrane-like texture, and it consists of three or five carpels, containing many seeds, and each having a separate style, and a pointed stigma. The flowers are very showy, from their large golden yellow petals and numerous stamens. The genus Androsæmum, the Tutsan, or Park-leaves, has been separated from Hypericum on account of its fruit being one-celled and one-seeded, with a fleshy covering, which yields a red juice when pressed. _H. calycinum_, with large yellow flowers and five tufts of stamens, is the handsomest species; but _H. perforatum_ is the true St. John’s Wort, which the country people used formerly to gather on midsummer eve, as a preservative against witchcraft.

ORDER XXXIX.—GUTTIFERÆ.—THE MANGOSTEEN TRIBE.

The only genus in this order that contains plants interesting to the English reader is Garcinia; and the most remarkable species are _G. Mangostana_, the Mangosteen, said to be the most delicious fruit in the world, and _G. Cambogia_, the tree producing the gamboge, which is a kind of gum that oozes out from the stem. Both are natives of the East Indies.

ORDER XL.—MARCGRAAVIACEÆ.

Exotic shrubs, mostly natives of the West Indies, with spiked, or umbellate flowers, and alternate leaves. Very seldom seen in Britain.

ORDER XLI.—HIPPOCRATACEÆ.

Exotic arborescent, or climbing shrubs, generally with inconspicuous flowers. Natives of the East and West Indies.

ORDER XLII.—ERYTHROXYLEÆ.—THE RED WOOD TRIBE.

Exotic shrubs, and low trees, remarkable from the redness of their wood, but with small greenish flowers. The leaves of _Erythroxylon Coca_ possess an intoxicating quality, and are chewed by the Peruvians, in the same manner as the Turks take opium.

ORDER XLIII.—MALPIGHIACEÆ.—THE BARBADOES CHERRY TRIBE.

Several species of Malpighia, the Barbadoes Cherry, are found occasionally in our stoves. The corolla of these plants, when closed, bears considerable resemblance to that of a Kalmia; but the flower when expanded is more like that of a Clarkia, from the long claws of the five petals, and the distance they are placed apart. Several of the species have their leaves and stems beset with stinging bristles, which adhere to the hands when touched. The fruit, which is eatable, but insipid, is a berry-like drupe, containing three one-seeded nuts. The species are natives of the West Indies, and they require a stove in England. The flowers are generally rose-coloured or purplish; but they are sometimes yellow. The common Barbadoes Cherry is called _M. glabra_, and its leaves are without stings. In Hiptage, another genus of this order, four of the petals of the flowers are white, and one yellow; and in Banisteria, the species are generally climbing shrubs, always with yellow flowers. Some of the species of Banisteria are occasionally found in stoves in this country, where their beautiful feathery yellow flowers have very much the appearance of those of the Canary bird flower (_Tropæolum peregrinum_).

ORDER XLIV.—ACERINEÆ.—THE MAPLE TRIBE.

The common Maple (_Acer campestre_) and the Sycamore (_A. Pseudo-Platanus_) are the only plants belonging to this order, that are natives of Britain; though so many kinds of ornamental Acers are now found in our parks and pleasure-grounds. Few trees are indeed more deserving of culture than the American Maples, both for their beauty in early spring, and for the rich shades of yellow and brown which their leaves assume in autumn. The Maple tribe is a very small one; it consists indeed of only the genera Acer and Negundo, and an obscure Nepal genus, of which there are no plants in Britain. Of all the Acers, one of the handsomest is the Sycamore tree (_A._ _Pseudo-Platanus_); the flower of this species (see _e_ in _fig._ 123) is of a yellowish green; and as in early spring, when it appears, we are delighted at the sight of any thing in the way of flowers, it really looks very beautiful. Before I began to study botany, I had never noticed the blossoms of the forest trees, and when I was shown the light-feathery flowers of the Lime, and the gracefully-drooping ones of the Sycamore, I was quite astonished. The flowers of the Sycamore grow in a drooping raceme; the calyx is divided into five parts, but as it is scarcely distinguishable from the petals, which are five in number, and placed alternately with the sepals, it appears to be in ten divisions (see _a_). These flowers are partly male and female (see _b_ and _c_), and partly perfect. In the perfect flowers there are eight stamens, and two stigmas; and the ovary when ripe expands into a curiously winged pod, called a samara (_d_), but differently shaped to the samara of the Ash, the thickened parts at the base of which contain the seeds. There is no albumen in the seed, which, when put into the ground, expands into two long thin cotyledons, (_a_ in _fig._ 124) which, if once pointed out, will always be known again instantly. If a ripe seed be opened when quite fresh, the cotyledons or seed leaves will be found within it, fresh, green, and succulent; and these leaves (_a_ in _fig._ 124), which rise above the ground as soon as the seed begins to germinate, differ widely in shape from the true leaves (_b_) which are serrated, and of a much thicker texture. The bracts of the Sycamore (_f_ in _fig._ 123) are thick and leathery, and of a rich dark brown. The leaves are serrated at the margin; and the lower ones are cut into five lobes; but those near the flowers have generally only three lobes (_e_), and in all the leaves, two of the lobes are not so deeply cut as the others.

There are many species of Acer, most of which are tall trees; and they are chiefly distinguished from each other by the shape of the leaves and of the samaras, or keys, the wings of which, in some species, are near together, as shown at _d_ in _fig._ 123, and in others widely apart, as in the common hedge Maple (_A. campestris_), and in the Norway Maples, as shown at _a_ in _fig._ 125. This figure represents the flowers of the Norway Maple (_Acer platanoides_), which are in what botanists call a corymb, and stand erect, instead of drooping like those of the sycamore. The leaves are deeply five-lobed, and the lobes are so coarsely toothed, that the teeth have almost the appearance of lobules. The buds of this plant in winter are large and red, and when they open in spring, the bracts (_b_) curl back over the scales (_c_). The leaves become of a clear yellowish red in autumn, and the whole plant is very ornamental. When a leaf of this tree is broken off, a milky sap issues from the broken petiole or leaf-stalk, which is of an acrid nature; differing in this respect, materially from the sap of the trunk, which is very sweet. Sugar indeed may be made from the sap of the trunk of almost all the Maples; but particularly in America, from that of the Sugar Maple (_Acer saccharinum_). The flowers of the red American Maple (_Acer rubrum_) are red, and as from their colour, and their appearing a fortnight before the leaves, they are very conspicuous, I have given a magnified representation of them in _fig._ 126, that my readers may have an opportunity of examining the male and female flowers from a living tree. In _fig._ 126, _a a_ are male flowers, having no stigmas; and _b b_ are female ones, having no stamens.

The leaves of _Acer rubrum_ become red in autumn. The Tatarian Maple differs from the other species in having entire leaves, and the samaras are red when young; but all the other kinds of Acer common in British gardens bear a strong family likeness to each other. The Ash-leaved Maple is now made into a separate genus, and is called _Negundo fraxinifolia_. This tree is easily distinguished from the Maples by its compound leaves, which resemble those of the Ash, and its long pea-green shoots, which have very few buds. The male and female flowers of the Negundo are on different trees, and they are so small as to be seldom seen, though the racemes of samaras or keys which succeed the flowers are very conspicuous. The Negundo is a native of America, and its leaves turn yellow in autumn.

ORDER XLV.—HIPPOCASTANEÆ, OR ÆSCULACEÆ. THE HORSE-CHESTNUT TRIBE.

This order contains only two genera; viz., Æsculus, the Horse-chestnut, and Pavia, the Buckeye; both of which are generally called Horse-chestnuts, though the genera are easily distinguished by their fruit, the husk of which is smooth in the Pavias, but rough in the true Horse-chestnuts. The buds of all the species of both genera are covered with bracted scales, most of which fall off when the leaves and flowers expand; and those of the common Horse-chestnut (_Æsculus Hippocastanum_) are very large, and covered with a kind of gum. Four large compound leaves, each consisting of five or seven leaflets, and a raceme of sixty-eight flowers, have been unfolded on dissecting one of these buds, before the leaves unfold in spring. The flowers of this species are produced in large, upright panicled racemes (see _a_ in _fig._ 127); and the leaves (_b_) are compound, consisting of five or seven leaflets, disposed in a palmate manner. Two of the inner bracts, which remain after the outer scales (which are very numerous) have fallen, are shown at _c_. I mention this particularly, as these remaining bracts have very much the appearance of stipules, and it is one of the characters of the Horse-chestnuts that their leaves are without stipules. The flowers consist of five petals, two of which (_d_ in _fig._ 128) are somewhat smaller than the others. Each petal consists of a broad blade or limb (_e_), and a very narrow claw (_f_). There are seven stamens, three of which (_g_) are shorter than the others. The filaments are inserted in the receptacle (_h_), and surround the pistil, which is hairy, and has a long style and a curved stigma (_i_). The ovary is two-celled, and each cell contains two ovules, but seldom more than one seed ripens. The nut (_k_) is large, and covered with a shining brown skin, which is strongly marked with the hilum. When put into the ground, the cotyledons do not appear in the shape of seed-leaves, but remain in the ground, and the plumule and radicle are protruded as shown in _fig._ 129. The Acorn germinates in a similar manner, as already shown in _fig._ 86 in p. 192.

The flowers of the different species of Æsculus vary considerably; as, for example, in the Scarlet Horse-chestnut (_Æ. rubicunda_), the calyx is tubular (see _a_ in _fig._ 130), and there are but four petals, the upper two of which (_b_) are narrower than the lower ones (_c_), and have bearded claws. This species has sometimes eight stamens. In the Yellow Horse-chestnut, or yellow flowered American Buckeye, the upper petals (_a_ in _fig._ 131) are very much smaller than the lower ones (_b_), and both have very long claws. There are four petals, which conceal the stamens, of which there are frequently only six. The seed of Pavia has only a small hilum, which resembles the pupil of an eye (see _fig._ 132); and hence the genus has received its American name of Buckeye. In one species (_P. macrostachya_), the nut is eatable, and very much resembles that of a Sweet Chestnut when boiled in milk. The stamens in this species are much longer than the petals, and they give a peculiarly light and elegant appearance to the flowers; which, unlike those of the other species, do not appear till the latter end of summer or autumn.

ORDER XLVI.—RHIZOBOLEÆ—THE CARYOCAR TRIBE.

Trees of large size, natives of tropical America. _Caryocar nuciferum_ produces the Suwarrow, or Butter-nut of the fruiterers’ shops.

ORDER XLVII.—SAPINDACEÆ.—SOAP-TREE TRIBE.

The only plant in this order which will grow in the open air in England is _Kölreuteria paniculata_, a beautiful tree, with very elegant leaves, and panicles of yellow flowers, which are succeeded by a bladdery capsule, which is divided into three cells in its lower part, though it is only one-celled above. The rind and pulp of the fruit of _Sapindus Saponaria_ are used as soap in those countries of which it is a native. The nuts of this plant are round and hard, and of such a shining black that they are made into buttons and beads by the inhabitants of Spanish America. The whole plant, if thrown into ponds containing fish, will intoxicate, and sometimes kill them. Another interesting plant belonging to this order is the Chinese fruit called Litchi (_Euphoria_ or _Nephelium Litchi_); which has its sweet eatable pulp enclosed in a kind of nut, much wrinkled on the outside; so that the fruit lies within the stone, instead of being on the outside of it. These hard, stone-like berries grow in loose racemes.

ORDER XLVIII.—MELIACEÆ.—THE BEAD-TREE TRIBE.

_Melia Azederach_, the Pride of India, or Indian Lilac, or Bead-tree, for it is known by all these names, is a native of Syria, which has become almost naturalised in the South of Europe, particularly near the Mediterranean. The leaves are bi-pinnate, the flowers are violet-coloured, and the fruit, which resembles that of the cherry, is of a pale yellow when ripe. The pulp is poisonous, and the stones are used for making rosaries in the Roman Catholic countries.

ORDER XLVIII*.—CEDRELEÆ.—THE MAHOGANY TRIBE.

This order was at first united to Meliaceæ by De Candolle, but it has been separated on account of its winged seeds. It contains, among other genera, the Mahogany tree (_Swietenia Mahagoni_), and the West Indian Cedar (_Cedrela_). The leaves of these trees are alternate and pinnate, with unequal-sided leaflets; and the flowers are in large spreading panicles composed of numerous little cymes. The fruit is capsular, and the seeds are winged. The genera contained in this order, all require a stove in Great Britain.

ORDER XLIX.—AMPELIDEÆ.—THE VINE TRIBE.

The natural order Ampelideæ contains several genera, but of these only the Vine and the five-leaved Ivy are common in British gardens. It seems almost ridiculous to talk of the flowers of the Vine, as the bunches, even when they first appear, seem to consist of only very small grapes, which gradually become large ones. The flowers, however, though small and insignificant, are perfect, and they have each a distinct and regularly formed calyx and corolla. The calyx of the common Grape (_Vitis vinifera_) is very small, and remains on till the fruit is ripe; there are five petals (_a_ in _fig._ 133), which never expand, but remain fastened together at the tip, detaching themselves at the base, when it is necessary that they should give room to the ripening stamens (_b_). The petals, which form a kind of extinguisher, when they are raised by the five stamens, fall off (_c_), and occasion the chaffy appearance observable in clusters of Vine-flowers. The ovary is, when young, in two cells, each containing two seeds; and it is crowned with a nearly flat, round stigma, without any style. When the fruit begins to swell, the ovary becomes filled with a pulp, which is solid, and not contained in bags like that of the Orange; and the dissepiment that divided the two cells gradually wastes away. Two, and sometimes three of the seeds also frequently disappear, so that four seeds are rarely found in the ripe grape. The seeds themselves are bony, and covered with a jelly-like matter; and when they are cut open, they are found to consist of a large quantity of hard albumen, with a very small embryo at the tip. The Vine is a climbing shrub, with lobed leaves, which are frequently deeply cut; the bunches in which the grapes are disposed are called branched or thyrsoid racemes (see 137), and the tendrils, by which the plant climbs, are supposed to be abortive peduncles, drawn out into these long, flexible, curling bodies, instead of producing bunches of grapes. The footstalks of the leaves are articulated, and will separate from the branch without tearing them. The different species of vines differ from each other chiefly in their leaves; but in the American grapes the calyx is sometimes entire, and sometimes the stamens and pistils are in different flowers.

The five-leaved Ivy, or Virginian Creeper (_Ampelopsis hederacea_), differs very little from the Vine in the botanical construction of its flowers. The calyx is, however, almost entire, and the five petals separate in the same way as those of other flowers; but in other respects they closely resemble those of the Vines. The berries are small, and not palatable, though they might be eaten with perfect safety. The leaves are palmate, and they are divided into three or five stalked leaflets. The stems are climbing and rooting; and the leaves take a beautiful deep red in autumn. The genus Cissus also belongs to this order.

ORDER L.—GERANIACEÆ.—THE GERANIUM TRIBE.

The order Geraniaceæ contains several genera of well-known plants, the most popular of which are _Pelargonium_, _Erodium_, and _Geranium_, signifying Stork’s-bill, Heron’s-bill, and Crane’s-bill, which differ very slightly from each other. The greenhouse Geraniums, which are all either natives of the Cape of Good Hope, or hybrids raised in Europe from the species originally imported, were, till lately, all included in the genus _Pelargonium_; but what were sections of that genus have, by some botanists, been now made separate genera. As probably, however, this rage for giving new and different names to divisions and subdivisions will not be generally adopted, I will not trouble my readers with any other distinctions than those between the three leading genera; and even these, I think they will allow, appear very trifling. The calyx of the Pelargonium is in five sepals, and two of them end in a kind of spur; which is, however, not very perceptible, as it runs down the peduncle or footstalk of the flower, and grows to it, so as to seem only a part accidentally enlarged. The corolla is in five petals, the upper two of which are generally larger, and differently marked to the others. Sometimes there are only four, and sometimes there are six petals; but these are exceptions to the general rule. The perfect stamens vary in number from four to seven; but there are always ten filaments, which are dilated, and grow together at the base; and I was quite delighted with the sparkling gem-like appearance of the membrane which they form when thus united, when I looked at it through my little microscope. In the plant now before me (a hybrid called the Duke of Sussex), the upper parts of some of the stamens have turned into little petals, retaining the white membrane-like part at the base, and thus curiously exemplifying the manner in which double flowers are formed, which is always by the metamorphosis of the stamens, or of the stamens and pistil, into petals. The pistil of the Pelargonium appears, when young, to consist of a five-celled ovary, with a long slender style, the tip of which is divided into five slender curved stigmas. The cells of the ovary are, however, five one-seeded carpels, each having a separate style; and though both the carpels and styles appear firmly grown together when young, yet, in fact, they only adhere to an elongation of the receptacle (see _a_ in _fig._ 134), which is here called the central axis, and from which, when ripe, they part with elasticity, and curl up, as shown at _b_; the styles, or awns, as they are sometimes called, being hairy inside.

The shape of the unripe seed-vessel, with its persistent calyx, is shown at _c_, and a detached seed at _d_. No plant hybridises more freely than the Pelargonium; and thus, the number of new kinds raised every year defies all description, and they have been so mixed and intermixed with each other, that it is not easy to say to what species the most splendid hybrids are allied. A few species, however, remain nearly unchanged, and the best known of these are _P. zonale_, the Horseshoe Geranium; _P. inquinans_, the common scarlet, the juice of the leaves of which is said to stain the fingers brown; _P. graveolens_, and _P. capitatum_, the rose-scented Geraniums, and _P. tricolor_. All the Pelargoniums have their flowers in heads or umbels; and the calyx in all of them remains on till the seeds are ripe. The seed-vessel, or fruit, as it is called by botanists, is long and pointed, forming some resemblance to the head of a stork; the ovary shrouded in the persistent calyx, representing the head of the bird, and the long styles the beak. The leaves vary in shape in the different kinds: sometimes they are roundish, as in the Horseshoe Geranium, and marked with a dark band or zone, whence the specific name _zonale_; and sometimes they are deeply cut, as in the rose-scented kinds: some are shrubby, and some herbaceous; and the stems of some species are warted, and the roots of others tuberous.

The genus Erodium consists principally of European plants, three of which are natives of England. The commonest of these (_Erodium cicutarium_) is called in many parts of England the Wild Geranium; and nearly allied to it, but less common, is _E. moschatum_. The principal points in which this genus differs from Pelargonium are, that the filaments of the stamens are very little united at the base; that there are always five filaments which bear anthers, and five that are sterile, and that the latter have each a gland at the base. The calyx is also without the spur, and the seed-pod is thought to resemble a heron’s head more than that of a stork. When it bursts, also, the styles, which are hairy inside like those of the Pelargonium, do not curl up in the same manner as in that genus, but spirally.