Part 78

The leaves are always opposite or verticillate. The flower is epigynous, ☿, 5-(or 4-) merous, with the usual sympetalous diagram; 2–5 carpels. The inflorescences are frequently dichasial. The sepals are small, reduced to teeth, and become almost entirely suppressed in the higher forms.--The flower is regular in Rubiaceæ and some Caprifoliaceæ, but in other genera of this latter order (especially of Lonicereæ) it is unsymmetrical. In several genera of the order first mentioned the loculi of the ovary contain many ovules, but in the last the number of loculi and ovules becomes reduced. This is to some extent connected with the nature of the fruit which is many-seeded in most instances, namely a capsule or berry, but in others nut-like. Endosperm is present.

The family on one side is allied to the Contortæ (not only through the Loganiaceæ but also through the Apocynaceæ), and may be regarded as an epigynous continuation of this family; on the other side it is allied to the Valerianaceæ and Dipsacaceæ. Many points of agreement with the Cornaceæ and Araliaceæ are also found, and in fact several Caprifoliaceæ are distinguished from these by hardly any other feature than the gamopetalous corolla.

Order 1. =Rubiaceæ.= Leaves opposite (or verticillate), undivided and entire, with interpetiolar stipules (Fig. 586). Flowers epigynous and hermaphrodite, regular, 4- or 5-merous with the usual arrangement (Figs. 585, 588–590); corolla gamopetalous, in æstivation often valvate; ovary frequently 2-locular.

There are no external characters which at once distinguish this exceedingly large order, as in many other natural orders (Compositæ, Umbelliferæ, etc.), but the opposite leaves with interpetiolar stipules form an excellent mark of recognition. It is divided into many sub-orders and groups, especially characterised by the nature of the ovary (1 or several ovules in each loculus), and of the fruit (schizocarp, berry, drupe, capsule).--The corolla is bilabiate in 4 genera; its æstivation in some is twisted; in Capirona, etc., the filaments are of unequal size. The ovary is semi-epigynous in Henriquezia, etc. In Morinda all the fleshy fruits coalesce into one multiple fruit.

=1.= CINCHONEÆ. The fruit is a 2-valved capsule, with many winged seeds (Fig. 585). Cinchona (Quinine, Fig. 584). Trees and shrubs with the foliage and inflorescence somewhat resembling Syringa; the corolla also being of a lilac colour, more or less salver- or funnel-shaped, and frequently edged with a fringe of hairs (Fig. 585), is somewhat similar to that of Menyanthes. Their home is the Andes from Bolivia to Venezuela, varying in altitude from 1–3000 metres. There are now large plantations in Java and E. India. ~(The name “quinine” is of Indian origin; that of the genus “Cinchona,” is from the Spanish Duchess Cinchon, who in 1638 first introduced the bark into Europe.) The following are closely allied: Cascarilla, Remijia, Ladenbergia, Manettia, Bouvardia, etc.~

=2.= GARDENIEÆ. Trees and shrubs, frequently having a many-locular berry. Randia, Gardenia, Genipa, Hamelia, etc.

=3.= COFFEEÆ. Only 1 seed in each of the two loculi of the ovary; the fruit is a drupe with 2 stones. Coffea has an ellipsoidal fruit about the size and colour of a cherry; the two thin-shelled, parchment-like stones are enclosed by a thin layer of pulp; the two seeds are flat on the side turned to one another, which has also a deep, longitudinal groove curving to the sides. The endosperm is hard, horny and greyish (without starch); the small embryo lies in the lower end near the circumference. The Coffee-plant (C. arabica) is a small tree, or more frequently, and especially in plantations, a shrub with large dark-green leaves and scented, white flowers. Its home is in Tropical Africa; it is now cultivated in many tropical countries. C. liberica, W. Africa.--Cephaëlis (C. ipecacuanha, Fig. 586; the roots are officinal).--~Psychotria, Chiococca, Ixora, Hydnophytum, Myrmecodia, etc.~

=4.= SPERMACOCEÆ. Chiefly small shrubs and herbs, many of which are weeds in tropical countries. The stipular sheaths bear numerous bristles at the edge. Spermacoce, Borreria, Diodia, Richardsonia, etc.

=5.= STELLATÆ. Herbaceous plants with verticillate leaves (Figs. 587, 588–590); the stipules are large, leaf-like, and resemble the lamina of the leaves, so that the leaves appear to be placed several in a whorl, while in reality there are only two opposite leaves, the stipules of which project freely, and are not erect (Fig. 587).

In some cases there are apparently 4 leaves in the whorl, and then 2 of these are leaves, and the other two are their interpetiolar stipules. When there are apparently 6 leaves, then the two of these which are opposite each other are leaves, and the other four are stipules; if there are several members in the whorl, then a division of the stipules has taken place. The proof of this theory is founded upon the fact that not more than 2 of the leaves of the whorl ever support buds (which, in addition, are seldom of equal vigour), and also that the whorls do not alternate with each other, which, according to the rules of the position of the leaves, they should do if all the members of a whorl had equal value. If there are, for instance, 4 members in two successive whorls, they stand right above one another, and do not alternate. The development and anatomical relations (the branching of the vascular bundles) also point to the same conclusion.~--All the other groups of the order have only 2 small scale-like interpetiolar stipules, or they form at the base of the leaf-stalks an interpetiolar sheath, having often a toothed edge (Fig. 586).--Another characteristic feature in this group is that the calyx is rudimentary, the corolla valvate (Fig. 588), and that each of the two loculi of the ovary has only 1 ovule. The fruit is a schizocarp dividing into 2 fruitlets (Fig. 590). ~The forms of the fruit, as well as many other characters, as, for example, the epigynous flower, the rudimentary calyx, the two free or almost free styles, present interesting analogous resemblances to the polypetalous order of the Umbelliferæ.~ This group has its home chiefly in the temperate regions of the northern hemisphere, especially about the Mediterranean; it is the only group which occurs in this country, represented by 4 genera.

FIG. 588.--Diagram.

FIG. 589.--Longitudinal section of flower.

FIG. 590.--Longitudinal section of fruit (3/1).]

Galium (Cleavers) is almost destitute of a calyx; it has a small 4-partite, rotate corolla, 4 stamens, and 2 free styles. The fruitlets are nut-like. The inflorescence is a paniculate dichasium passing into helicoid cymes.--Asperula (Woodruff) is distinguished from the above by its salver- or funnel-shaped corolla. 1 style.--Rubia (Madder, Figs. 587–590) has almost the same form of corolla as Galium, but (most frequently) a 5-merous flower, and the fruitlets are “drupes.” ~Sherardia (Field Madder); the flowers are clustered in closely arranged cymes surrounded by an involucre; the calyx has 6 distinct teeth, while the number of petals and stamens is 4. The corolla is funnel-shaped.--Vaillantia. Crucianella.~

The DISTRIBUTION OF SEEDS, in some instances, is promoted by hooked appendages on the fruitlets (e.g. Galium aparine).

The small flowers of the Stellatæ are frequently collected in compact inflorescences, and are therefore rendered more conspicuous; slight protandry is found in some, self-pollination in the species which are less conspicuous. Many species are heterostylous. Myrmecodia, Hydnophytum, and other genera have large tubers (hypocotyledonous stems), whose labyrinthine cavities and passages are inhabited by ants.

About 4,500 species; tropical or sub-tropical except the Stellatæ; especially American. The tropical ones are mostly trees.--Several are ~OFFICINAL~ on account of the large amount of alkaloids and glycosides which they contain. The most important are the Cinchonas (Cinchona calisaya, C. succirubra, C. officinalis, C. micrantha, etc.), whose bark contains the well-known febrifuge and tonic, Quinine, Cinchonin, etc.; Quinine is also found in Exostemma, Ladenbergia, and Remijia. The root “Ipecacuanha” (an emetic) from Cephaëlis ipecacuanha (Brazils). Caffeine is officinal. The use of the seeds of the coffee plant (“the beans”) was first known in Europe in 1583.--There are only a few which contain aromatic properties, principally among the Stellatæ (coumarin in Asperula odorata, the Woodruff), in which group colouring materials are also found. The root and root-stalks of Rubia tinctorum, the Madder (S. Eur., Orient., Fig. 587), were formerly largely used for dyeing, but are now superseded by the analine colours. Red dyes are also obtained from the roots of species of Asperula and Galium. Gambier is a splendid colouring material, obtained from Uncaria gambir (S.E. Asia), which is used in dyeing and tanning.--The order does not furnish many ornamental flowers.

Order 2. =Caprifoliaceæ.= This order agrees with the Rubiaceæ in having opposite leaves and an epigynous flower, most frequently 5-merous with the ordinary tetracyclic diagram, but in some species it is zygomorphic; the corolla has imbricate æstivation, carpels 3–5, most frequently 3 (not 2, which is the most usual number in the Rubiaceæ). The fruit is generally a berry or a drupe, but the most important, and in any case most easily recognisable feature, is the absence of stipules; in exceptional cases, where they are present, they are not interpetiolar, and are most frequently small.--~The majority of plants belonging to this order are shrubs or trees. Compound leaves sometimes occur. Stipules only appear in a few species of Lonicera, Sambucus and Viburnum; in the common Elder (Sambucus nigra) they are in some instances glandular and small, but in other cases larger and more leaf-like (upon long, well-developed shoots); in the Dwarf Elder (S. ebulus) they have the normal leaf-like form; in Viburnum opulus they are present as narrow lobes at the base of the petiole; in others they are completely absent. The leaves are frequently penninerved, rarely palminerved. The calyx, as in the Stellatæ and Aggregatæ, is often very insignificant.~

=1.= LONICEREÆ, HONEYSUCKLE GROUP. This has campanulate or tubular corollas which are often zygomorphic; in connection with the length of the corolla the style is long, filamentous, and most frequently has a large, capitate stigma. There are several ovules in the loculi of the ovary, and the fruit is most frequently a berry.

Lonicera (Honeysuckle). Shrubs, sometimes twiners. The corolla in some species is considerably bilabiate (Fig. 591), with 4 lobes in the upper lip, and 1 in the under lip, but in others more regular, tubular, or campanulate. The flowers are either borne in capitate inflorescences, which are compound and formed of closely compressed 3-flowered dichasia (sect. Caprifolium), or in dichasia with 2 flowers (the terminal flower is wanting). The ovaries and fruits coalesce in some (sect. Xylosteum). ~The opposite leaves in some species unite with each other and form a broad collar encircling the stem (Fig. 591). Above the primary bud 1–2 accessory buds are often found in the leaf-axils.--Diervilla (Weigelia); with a 2-locular, 2-valved capsule.--Symphoricarpus (Snowberry) has an almost regular, funnel-shaped corolla; a peculiar feature is found in the ovary which has 4 loculi, the 2 median having many ovules in 2 rows, all of which are aborted; the 2 lateral ones, on the other hand, each have only 1 ovule which is developed. Different forms of leaves are frequently found on the same branch; they are entire or lobed.~

=2.= SAMBUCEÆ, ELDER GROUP (Fig. 592). This has a rotate, regular corolla, extrorse anthers, a very short and thick (or almost absent) style, with tripartite stigmas, and only 1 pendulous ovule in each of the 3 (-5) loculi of the ovary. The fruit is a “drupe” with 1–3 (-5) stones. The inflorescence is made up of cymes grouped in an umbel-like arrangement.

Sambucus (Elder, Fig. 592) has imparipinnate leaves and a “drupe” with 3 (-5) stones. Between the calyx and the style a disc remains on the apex of the fruit. S. nigra with black fruit; S. racemosa with red fruit; S. ebulus is a perennial herb; the others are woody.--Viburnum (Guelder-rose) has simple leaves (penninerved or palminerved, entire, dentate or lobed), and a “drupe” with only 1 stone, which is compressed, cartilaginous, and parchment-like; 2 of the loculi of the ovary are aborted. ~(In V. opulus the marginal flowers of the inflorescence are barren, and in that case their corollas are generally specially large; the cultivated Viburnum has only barren flowers, with large corollas.)~

=3.= LINNÆEÆ. Linnæa borealis (the only species) is an extreme form of the order; it has a 2-flowered dichasium, funnel-shaped, slightly bilabiate corollas (2/3); 4 didynamous stamens. Two of the 3 loculi of the ovary have several ovules which are not developed, while the third has only 1 ovule, which developes into a seed. The fruit is a nut, which is enveloped by the two large bracteoles, which are covered by sticky, glandular hairs, and serve as a means of distribution. It is a small undershrub.

In cases where the flowers are small, as in Sambucus and Viburnum opulus, they are rendered conspicuous by being arranged in closely-packed inflorescences; they are massed together and form large surfaces, and in the last named are still more conspicuous on account of the barren, but large ray-flowers, which are of service in this respect. Honey is secreted in the nectaries at the base of the styles. In the genera with rotate flowers, as Viburnum and other Sambuceæ, the honey lies so exposed and in such a thin layer, that only flies and insects with short probosces can procure it; bees, however, visit these flowers for the sake of the pollen. There is hardly any nectar in the Elder; self-pollination frequently takes place. The flowers of the Caprifoliaceæ, which, with their long corolla-tube are adapted for evening-and night-flying insects with long probosces, open in the evening, and at that time give off their strongest scent.

DISTRIBUTION. 230 species; especially outside the Tropics in the Northern Hemisphere. In this country they are found especially in hedges and as under-shrubs.--OFFICINAL: the flowers and fresh fruits of the Elder (S. nigra), the fruits (“berries”) being also used in the household. ORNAMENTAL SHRUBS: species of Lonicera, Symphoricarpus, Diervilla, which are chiefly from N. Am., Abelia and Viburnum.

Family 34. =Dipsacales.=

The leaves are opposite and without stipules. The flower (Figs. 593, 595, 598, 599, 600) is epigynous, zygomorphic or asymmetrical, 5-merous with S5, P5, stamens typically 5, but by suppression never more than 4, sometimes less, carpels 3–2. The calyx is more or less insignificant, and almost suppressed in the extreme forms. The ovary has 3–1 loculi, but only one loculus has an ovule, which is pendulous with the micropyle turned upwards (Fig. 594). Fruit a nut. Embryo straight, with the radicle pointing upwards (Fig. 597), without or with endosperm.

The inflorescences are distinct dichasia in Valerianaceæ, but in Dipsacaceæ and Calyceraceæ they are crowded together into capitula.