Part 52

_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.

[_Adoxa_, which was formerly classed in this order, appears, according to recent investigations, to be more properly placed among the Saxifraginæ.]

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.

This family is closely allied to the Rubiales through the Valerianaceæ, which have almost the same structure as many of the Caprifoliaceæ. It attains the highest development in the Dipsacaceæ, which are composite plants, but differs from Compositæ in the position of the ovule, etc.

Order 1. =Valerianaceæ.= Herbaceous plants or under-shrubs with opposite leaves, often pinnate; stipules absent. The flowers are borne in _dichasia_ and in _scorpioid cymose inflorescences_ and are _entirely without any plane of symmetry_ (Fig. 593). The calyx and corolla are 5-merous, but the calyx is frequently very insignificant and ultimately a pappus, as in Compositæ; the corolla is frequently saccate or produced into a spur at the base. Most frequently, only 3 (4–1) of the 5 stamens are developed; these are free. Carpels =3=, which form an inferior _ovary_, often with 3 _loculi_, but only _1 of the loculi_ contains =1= _pendulous, anatropous ovule_ (Figs. 593, 594 _A_), the other loculi are empty and shrink up more or less completely. (Compare Fig. 593 _A_, _B_). Style 1, stigma tripartite. Endosperm absent; embryo straight, with the radicle directed _upwards_.

The inflorescences are dichasia, or unipared scorpioid cymes with the branches developed in the axil of the second bracteole. Both the bracteoles are generally present and frequently form 4 very regular, longitudinal rows on the branches of the inflorescence.--5 stamens do not occur (except perhaps in _Patrinia_). The suppression of stamens and carpels takes place most readily on the anterior side of the flower and that turned towards the first bracteole (_a_) (Fig. 593), whose branch is suppressed in the dichasium; after this the posterior median stamen is next suppressed.

By the vegetative characters as well as by the inflorescence and the flower, the order is allied to the Caprifoliaceæ and especially to the Sambuceæ.

In the least modified (oldest) forms, _Patrinia_ and _Nardostachys_, there is an almost regular flower, a 5-merous calyx, 4 stamens, and 3 loculi in the ovary, 2 of which however are barren. The stamens in _Valerianella_ are reduced to 3, in _Fedia_ to 2 (posterior), and the calyx is less distinctly 5-dentate; the 2 empty loculi in the ovary are still visible. _Fedia_ has a small spur at the base of the corolla. _Valeriana_ has a very reduced, hair-like calyx (pappus), an unsymmetrical, salver-shaped corolla with a _sac-like_, nectariferous spur at the base, 3 stamens and only 1 loculus in the ovary (Figs. 594, 593). _Centranthus_ (Fig. 593) is still further reduced. The corolla has a spur and only 1 stamen; ~unipared scorpioid cymes with 4 rows of bracteoles. In the last two genera there is a peculiar wall in the corolla-tube, which divides it longitudinally into two compartments (indicated by a dotted line in Fig. 593), one of which encloses the style. This wall is low in _Valeriana_, but in _Centranthus_ it reaches as far as the throat.--The rays of the _pappus_ are pinnately branched and rolled up before the ripening of the fruit. 12–20 in number (Fig. 594 _A_, _B_).~

_Val. officinalis_ and others are protandrous: in the first period the stamens project from the centre of the flower (Fig. 595 _a_), the stigmas in the second (_b_) when the stamens have become bent backwards. (_V. dioica_ is diœcious with large ♂-and small ♀-flowers).--275 species; especially from the temperate and colder parts of the northern hemisphere of the Old World, Western North America and the Andes.--_Bitter_ properties are characteristic, such for instance as the volatile acid and volatile oil of _Valeriana_; these occur especially in the rhizomes. OFFICINAL; the rhizomes of _V. officinalis_.--The true Indian “Nardus,” an important medicine and perfume in India, is extracted from _Nardostachys_ (Himalaya). A variety of _Valerianella olitoria_ is sometimes used as salad.

Order 2. =Dipsacaceæ= (=Teasels=). Herbs with _opposite_ leaves without stipules. The flowers are situated in compact capitula each with an involucre. A characteristic feature of the order is that _each flower_ of the capitulum has a _gamophyllous_ “_epicalyx_” (Figs. 597, 599, 600), which envelopes the inferior ovary. The flowers (Figs. 599, 600) are ☿, 5-merous (S5, P5, stamens typically 5, G=2=), but the calyx often expands at the edge into a membrane with 5, or an indefinite number of bristles or teeth (pappus, Figs. 597, 600), and the _zygomorphic, funnel-shaped corolla_ is sometimes 5-lobed and bilabiate (2/3), but most frequently 4-partite (Fig. 599), the two lobes of the upper lip coalescing into one lobe, as in certain Labiatæ, _Veronica_ and _Plantago_; the æstivation is _imbricate_.

_The stamens are never more than 4_, the posterior one _remaining undeveloped_; they _usually have free anthers_ which generally project considerably (Fig. 599). The ovary is unilocular with 1 _pendulous_ ovule and bears 1 _undivided style_; fruit a nut with 1 _seed, containing endosperm_ and with the radicle turned _upwards_ (Fig. 597).

The flowers do not always open in centripetal order, a fact which may be observed especially in the Dipsacaceæ, in which a zone of flowers round the centre of the capitulum opens first, and the flowering then proceeds both upwards and downwards (Fig. 598). This has probably some connection with the fact that the capitulum has arisen from the coalescence of several dichasial inflorescences. In species of _Scabiosa_ the flowers open simultaneously at the circumference, or in a zone at the centre.--The morphological explanation of the “_epicalyx_” is not quite certain; in all probability it is formed from two united bracteoles, for an “epicalyx” is distinctly formed in this way in one of the Valerianaceæ, _Phyllactis_.--The _ray-flowers_ are larger and more irregular, labiate or ligulate, than the disc-flowers, yet not in so high a degree as in the Compositæ.

=A.= A scarious bract to each flower. _Scabiosa_ has a 5-lobed corolla; the “epicalyx” has a dry, scarious, often finally large collar, and the true calyx is formed of long bristles (generally 5) (Fig. 597). _Succisa pratensis_ (Devil’s-bit) has a 4-lobed corolla, the collar of the “epicalyx” is herbaceous; the calyx as in the preceding.--_Pterocephalus._--_Dipsacus_ (Teasel); large, spiny and stiff-haired herbs with capitula, or short, thick spikes on which both the involucral-leaves and bracts project considerably, and are stiff and spinose (Fig. 598). The “epicalyx” has short teeth, or is almost entire. ~The leaves of the stem unite together in pairs, so that shallow cups are formed round the stems in which rain-water may collect.--_Cephalaria._--_Morina_: the flowers are falsely verticillate as in the Labiatæ; the calyx has 2 laterally-placed, entire, or emarginate lobes; 2 stamens, or 2 large and 2 small ones.~

=B.= Bristles, but _no_ true bract to each flower. _Knautia_; the corolla is 4-partite, the calyx cup-like, with many bristles or teeth on the edge.

POLLINATION is in many species effected by insects. The honey is secreted by a ring round the base of the style. The flowers in our native species are considerably protandrous. Gynodiœcious flowers also occur.--150 species; especially in the Mediterranean and the Orient; the order is not represented in the South Sea Islands, Australia and America.--The heads of the true Teasel (_Dips. fullonum_) are used for carding wool, on account of the elastic bracts, which are hooked at the point. The order has bitter properties; tanin, etc.; but no species are used in medicine or the household.--_Scabiosa atropurpurea_, etc., are used as ornamental plants.

Order 3. =Calyceraceæ.= This order resembles the Compositæ in the valvate æstivation of the corolla and the more or less united stamens, and the Dipsacaceæ in the undivided style, pendulous ovule and endosperm. The calyx is frequently composed of 5 distinct scales. An “epicalyx” is wanting.--20 species; America.

Family 35. =Campanulinæ.=

The flower is _epigynous_, perfect, with 5 sepals, 5 petals, and 5 stamens in regular alternation, and =3= (2–5) carpels. The sepals in all cases are _distinct_, but narrow and pointed, so that the æstivation is open. The corolla is gamopetalous with (as in the Compositæ) _valvate_, or slightly infolded-valvate æstivation. The stamens are nearly always _situated on the torus_ without being united to the corolla (Figs. 601, 604). The anthers adhere or unite and form a tube with introrse anthers from which the pollen is swept out by the projecting, brush-like hairs on the style (as in the Compositæ). The ovary is =3=-(2–5) locular, _many ovules_ in each loculus. The fruit is generally a _many-seeded_ capsule (or berry). Embryo in the centre of a fleshy _endosperm_.--The majority are herbs with scattered leaves, without stipules. The presence of _latex_ and _inulin_, together with the tubular formation of the anthers, the pollination, etc., indicate a relationship with the Compositæ.

The _Cucurbitaceæ_ are by some authorities placed in this family as being most closely related to the Campanulaceæ. Although the corolla is most frequently gamopetalous, and other similarities to the Campanulaceæ are present, yet on account of the structure of the ovule, and for other reasons, the Cucurbitaceæ are here placed in the Choripetalæ. The Campanulinæ without doubt proceed upwards to the Compositæ, with which, in addition to the occurrence of inulin and laticiferous vessels (Cichorieæ), there are many corresponding features both in the structural and biological relations (epigyny, valvate æstivation of the corolla, tendency of the anthers to adhere or unite, protandry with a stylar-brush, etc.) The inflorescence of _Jasione_ is almost identical with that of the Compositæ.

Order 1. =Campanulaceæ= (=Campanulas=). The flowers are _regular_ and in some only semi-epigynous, 5-merous, except in the gynœceum which is 3-merous (the unpaired, median carpel being generally posterior), more rarely 2–5-merous, and has a corresponding number of stigmas and loculi in the ovary; the placentation is axile with a large number of ovules. The median sepal is posterior. The stamens frequently have broad, free bases (Fig. 601 _H_) which cover the nectariferous upper surface of the ovary; the anthers only fit loosely together, and become separated as soon, as the pollen is shed (Fig. 601 _G_), 1 long style, which is studded by sweeping-hairs (stylar-brush), which ultimately become invaginated; the stigmas do not unfold until the stamens have shed the pollen (Fig. 601 _E_, _G_). Fruit a capsule.--Herbs, more rarely under-shrubs or shrubs, with latex and scattered, undivided leaves without stipules. The inflorescence is most frequently a raceme or spike _with_ terminal flower.

=A.= Capsule opening at the side by pores and small valves: _Campanula_ (Canterbury-bell); the corolla is bell-shaped, rarely almost rotate; capsule obconical. ~The pores of the capsule are found near the top of the fruit when it is erect, and near the base when it is pendulous, so that the seeds are not liberated unless the capsule is forcibly shaken, and they are thus ejected to a considerable distance.~--_Phyteuma_ (Rampion) has free petals, which for a long time adhere at the apex and form a tube round the stamens (Fig. 601); inflorescence compact, spike-like or capitate, in the latter case resembling that of the Compositæ, and frequently with an involucre similar to the one possessed by this order. ~_Specularia_ (rotate corolla, prismatic capsule), _Michauxia_ (flower 8-merous).--_Symphyandra_ has syngenesious anthers.~

=B.= Capsule with valves at the apex, loculicidal dehiscence: _Jasione_; the petals are almost free. The anthers are united at the base (syngenesious). The flowers are situated in capitate umbels with involucres.--_Wahlenbergia_; _Platycodon_.

=C.= Berry: _Canarina_; flower, 6-merous; leaves opposite.

Protandry is general (Fig. 601). 510 species; principally in temperate countries. Several genera furnish ornamental plants, but are of little use for other purposes. The roots of some _Campanula_-and _Phyteuma_-species are large and may serve as pot-herbs (_C. rapunculus_, _P. spicatum_).

Order 2. =Cyphiaceæ.= In this order the corolla is zygomorphic and the stamens free, hence it is intermediate between orders 1 and 3.--About 24 species; Africa.

Order 3. =Lobeliaceæ= (=Lobelias=). This order may briefly be described as Campanulaceæ with _zygomorphic_ flowers and anthers _united into a tube_, in most cases slightly bent; generally 2 carpels and an _inverted_ position of the flower, _i.e._ the median sepal is turned anteriorly (Fig. 602) (a position which is found to occur within the Campanulaceæ). A twisting of the peduncle takes place even before flowering (as in the Orchids) so that the ordinary position of the 5-merous Dicotyledons appears to be restored. The zygomorphy of the flower is especially present in the corolla, which has a _bipartite_ under-lip and a _tripartite_ upper-lip, and is, in _Lobelia_, anteriorly (apparently posteriorly) deeply cleft (Fig. 602). There is 1 style, but the stigma is capitate and bilobed and surrounded at its base by a _whorl of hairs_, which assists in pollination (as a stylar-brush) in the same manner as the sweeping-hairs in the Campanulaceæ and Compositæ. There is _no terminal flower_ in the spicate, or racemose inflorescences.--_Lobelia_ has a capsule, several others have berries. ~_Isotoma_ (regular flower); _Heterotoma_ has a spur; _Siphocampylos_; _Lysipoma_ (pyxidium); _Clintonia_ (1–locular fruit). _Metzleria_ (all the petals are free).~

Entomophilous and protandrous. About 500 species, especially in the Tropics; in this country, _L. dortmanna_ (margin of lakes).--Several are cultivated in gardens and conservatories as ornamental plants (_Lobelia bicolor_, _erinus_, _fulgens_, etc., _Siphocampylos_, _Centropogon_). The latex of several species of _Tupa_ is poisonous; caoutchouc is also obtained from them. OFFICINAL: “herba _Lobeliæ_” (the alkaloid lobeline) from the poisonous _L. inflata_ (N. Am.).

Order 4. =Goodeniaceæ.= Chiefly Australian (200 species), closely related to Orders 3 and 5, but without latex. The style is provided with a “collecting-cup” which receives the pollen before the flower opens; it has a small, hairy aperture through which the pollen is forced out by the stigmas, and through which they emerge when the pollen is shed; it is sensitive and exhibits movements when touched.--Herbs, under-shrubs, less frequently shrubs. _Goodenia_, _Leschenaultia_, _Scævola_.

Order 5. =Stylidiaceæ= (or =Candolleaceæ=); 100 species, the majority Australian; zygomorpbic flowers, but with the ordinary position. The anterior petal is very small. The chief characteristic feature is the presence of only 2 stamens (with extrorse anthers) which are united with the style and form a _stylar-column_; this is bent like a knee and sensitive at the bend to such a degree that when touched it jerks violently across the flower to the opposite side and then loses its sensitiveness.--Herbs, less frequently under-shrubs. _Stylidium_ (_Candollea_).

Family 36. =Aggregatæ.=

The flowers, which are borne in “capitula” (Figs. 605, 610), are _epigynous_ (Fig. 605 _C_, _D_), _5-merous_ in the calyx, corolla and andrœcium, the corolla is _valvate_ in æstivation, with =2= carpels (S5, P5, A5, G2). The anthers are united into a tube (syngenesious) (except _Ambrosieæ_) which surrounds the bifid style. There is never more than =1= _loculus_ in the ovary, with =1= _erect_, anatropous ovule. The fruit is a 1–seeded nut (cypsela), with thin pericarp, the calyx generally persists as a tuft of hairs (_pappus_) (Fig. 606) on the summit of the fruit. Embryo _without endosperm_; the radicle _directed downwards_.

Only 1 Order: Compositæ.

With respect to the inflorescence and the development of the individual flowers, there is a very close resemblance to the Dipsacaceæ, which stand on the same plane of progression as the Compositæ. But while the latter are allied to Campanulinæ as the last stage in the process of evolution, the Dipsacaceæ form the final stage of the Rubiales-Dipsacales.

Order =Compositæ=. (For the principal characteristics compare those of the family.) The Compositæ are chiefly herbs, but trees and shrubs also occur in tropical countries. The leaves may be scattered or opposite, but have no stipules. The outer leaves of the _involucre_ as a rule are barren, especially when numerous and imbricate, while the innermost ones support the ray-flowers of the capitulum; in a few instances all are fertile (_e.g._ _Tragopogon_, _Tagetes_). The CAPITULA are many-flowered, with the exception, _e.g._ of _Echinops_, which has 1-flowered capitula (see page 570). The capitula are again arranged in inflorescences, most frequently corymbose with centrifugal order of development. The _form of the receptacle_ is an important character for the division of the genera (flat, convex, conical), and also the _presence of scales_; these may be one scale (bract) for each flower (Fig. 610 _br_), or a large number of bristles, which do not each correspond to a leaf, or the receptacle may be entirely without covering (_naked_). The flowers open in acropetal order in each capitulum. All the flowers in a capitulum may be of the same _sex_, and their form and colour are in that case the same, or the sexes may be different, in which case the form and colour are also most frequently different: the ray-flowers have projecting labiate or ligulate corollas, while the disc-flowers have tubular corollas. As a rule in the latter case the ♀ flowers are at the circumference, and the ☿ in the centre, less frequently ♀-flowers at the edge and ♂-flowers in the centre. The ray-flowers in some genera are neuter (_e.g._ _Centaurea_). Some are diœcious.