Part 76

The flowers are hypogynous and zygomorphic (in Boraginaceæ and Cordiaceæ, however, they are regular, except Echium and Anchusa arvensis). The calyx is gamosepalous, the corolla bilabiate (except in the two orders mentioned), mostly after 2/3, i.e. divided into a 2-leaved posterior portion, and a 3-leaved anterior portion. The æstivation of the corolla is nearly always descending.--In Boraginaceæ and Cordiaceæ there are 5 stamens of equal length; in the other orders 4 didynamous ones, or only 2 fertile; the posterior stamen is sometimes developed as a staminode, sometimes fertile (in Stilbaceæ). The ovary is formed of 2 median carpels (except some Verbenaceæ), with (1-) =2= ovules on each carpel; in the majority of the orders it is, however, divided by a false partition-wall between the dorsal and ventral sutures, into =4= loculi, each of which is often raised independently, causing the style to be situated in the depression between the four lobes (“gynobasic” style, Figs. 572, 573, 575, 579). The fruit in these orders most frequently becomes a 4-partite schizocarp with nut-like fruitlets. The other orders have a 1(-2)-locular ovary.--The leaves are simple, without stipules.

The family is related to (and proceeds from) the Tubifloræ, especially Convolvulaceæ, which has an almost similar construction of the ovary. It is doubtful whether the Cordiaceæ and Boraginaceæ should be classed with the others.

The orders are: 1, Cordiaceæ; 2. Boraginaceæ; 3, Verbenaceæ; 4, Labiatæ; 5, Selaginaceæ; 6. Globulariaceæ; 7, Stilbaceæ.

Order 1. =Cordiaceæ= unites Convolvulaceæ and Boraginaceæ. Tree-like plants with 5-(4–10) merous flowers, doubly bifid style, and drupe with 4 or less loculi. No endosperm; cotyledons folded.--185 species; tropical.

Order 2. =Boraginaceæ.= The vegetative parts are very characteristic: herbs with cylindrical stems and scattered, undivided, nearly always sessile, entire leaves, without stipules, and generally, together with the other green portions of the plant, covered with stiff hairs, consequently rough and often even stinging (hence the other name for the order Asperifoliæ). The inflorescences are unipared scorpioid cymes with the branches coiled spirally (“helicoid,” Fig. 573) before the flowers open. The flower is perfect, regular (obliquely zygomorphic in Echium and Anchusa arvensis), hypogynous, gamopetalous: S5, P5 (often with ligular outgrowths), A5, G2, but each of the two loculi of the ovary becomes divided by a false partition-wall into two, each of which contains one pendulous anatropous ovule with the micropyle turned upwards; the four loculi arch upwards, so that the ovary becomes 4-lobed, and the style is then, as in the Borageæ, placed at the base (“gynobasic”) between the four projections (Figs. 572, 573). The fruit is a 4-partite schizocarp with four nut-like fruitlets (Fig. 572).--Endosperm is wanting (except in Heliotropium); the radicle is turned upwards.

The INFLORESCENCES are often double unipared scorpioid cymes; the bud of the second bracteole is developed, that of the first suppressed; in some cases both the bracteoles are suppressed (Myosotis, Omphalodes, etc.), but in other instances all the first bracteoles (a) only are suppressed, and the others are then situated in two rows towards the under side of the coiled axis, while the flowers are situated on the upper side. Displacement of the branches or of the floral-leaves sometimes takes place. The flowers are often red at first, and later on become blue or violet; they hardly ever have any smell. The fruit entirely resembles that of the Labiatæ, but the radicle of the latter is turned downwards. The fruitlets present small differences which have systematic importance; they are hollow or flat at the base, attached to a flat or columnar receptacle, etc.

=1.= HELIOTROPIEÆ. This group deviates from the characteristics mentioned above in the undivided ovary and terminal (“apical”) style. In this, as well as in the fact that in some genera (Tournefortia, Ehretia, etc.) the fruit is a drupe, it connects this order with the Cordiaceæ. Heliotropium, Tiaridium, and others have schizocarps.

=2.= BORAGEÆ, BORAGE GROUP. Style gynobasic; fruit a schizocarp.

=A.= The throat of the corolla is without ligules, or with very small ones.--Pulmonaria (Lung-wort); funnel-shaped corolla; a whorl of hairs in the corolla-throat.--Echium (Viper’s-bugloss) has zygomorphic flowers, the plane of symmetry almost coinciding with that of the very well-developed inflorescence (through the fourth sepal); the corolla is obliquely funnel-shaped, the style is more deeply cleft at the apex than in the others; stamens 2 longer, 2 shorter, and 1 still shorter.--Cerinthe has a tubular corolla with five small teeth and two bilocular fruitlets. The bracts are large and leafy, and, like all the rest of the plant, are almost glabrous.--A few Lithospermum-species have a naked corolla-throat; others have small hairy ligules, which do not close the corolla-throat. The fruitlets are as hard as stone, owing to the presence of carbonate of lime and silica.--Mertensia (Steenhammera); Arnebia; Nonnea (small ligules).

=B.= The corolla-throat is closed by, or in any case provided with ligules, i.e. scale-like bodies or small protuberances, situated in the throat of the corolla opposite the petals, and which are invaginations or internal spurs of the petals (Fig. 572 D).--The nuts in Cynoglossum (Hound’s-tongue) bear hooked bristles over the entire surface, or, in Echinospermum, only on the edge. The following have smooth nuts:--Symphytum (Comfrey) has a cylindrical, campanulate corolla, and prolonged-triangular, pointed ligules.--Borago (Borage) has a rotate corolla with projecting, emarginate ligules; the stamens have a horn-like appendage, projecting upwards from the back of the filament. The fruitlets are hollow below.--Anchusa (Alkanet, Fig. 572). The corolla is salver-shaped; the ligules small, hairy protuberances. A. (Lycopsis) arvensis has an S-curved corolla-tube.--Myosotis (Forget-me-not, Fig. 573); rotate corolla with small (yellow) protuberances in the throat; scorpioid cyme without floral-leaves; fruitlets flat.--Omphalodes; fruitlets hollow at the back, with a scarious, turned-in, toothed edge.--Asperugo (Mad-wort); the calyx grows after flowering, becoming large, compressed, and deeply bifid.

CROSS-POLLINATION is most commonly effected by insects (especially bees). There are a great many contrivances for pollination; some flowers are protandrous (Echium vulgare, Borago officin.), others are heterostylous (long-and short-styled: Pulmonaria officin.); the corona (ligules) is a protection against rain, and excludes certain insects. Some are barren when self-pollinated (Pulmonaria officinalis, Echium vulgare); others which have but little honey, may, failing insect-pollination, fertilise themselves, and in Myosotis versicolor this regularly occurs by the growth of the corolla during flowering, so that the anthers are brought into contact with the stigma. Honey is secreted on the hypogynous disc.--About 1,150 species, growing especially in the northern temperate zone, Mucilage is found (e.g. in the officinal root of Cynoglossum officinale, in the root of Symphytum): red dyes are found in some roots (e.g. Alkanet-root, the root of Alkanna tinctoria, which is also medicinal; S. E. Europe, Asia Minor); some are poisonous: Cynoglossum, Echium, Anchusa, etc. Several species are ornamental plants. Heliotropium (Peru) is cultivated chiefly on account of its pleasant scent; essential oils are otherwise very rare.

Order 3. =Verbenaceæ.= The majority are shrubs; a few are herbs or trees (Teak-tree); some are lianes. The branches are often square. The leaves are opposite or verticillate, without stipules; in some compound. The inflorescences are racemes, spikes, capitula, or dichasia. Five sepals; five petals in a gamopetalous, zygomorphic corolla, which is often bilabiate, but rarely to such an extent as in the Labiatæ, and the upper lip in some is larger than the under, in others smaller; stamens four didynamous, or two; the ovary is entire (not grooved or divided), 1- or 2-locular, or, as in the Labiatæ, divided into four loculi with an erect ovule in each, but in some the anterior carpel is suppressed. One terminal style. The fruit is, e.g. in Verbena, a 4 partite schizocarp with nut-like fruitlets; in Vitex (digitate leaves) a drupe with a 4-locular stone; in Clerodendron a similar fruit, with four free stones; in Lantana a bilocular stone, or two unilocular stones. The radicle is turned downwards. Endosperm small or absent.--Lippia, Stachytarpheta, Bouchea, Priva, Citharexylon, Callicarpa, etc.--The Verbenaceæ are closely allied to the Labiatæ; they differ especially in the ovary not being 4-lobed with gynobasic style, but undivided, almost spherical or ovoid with a terminal style. Again, the leaves are not so constantly opposite, and the inflorescences are various.

730 species; especially in the Tropics; there are several in America, especially Lantana-species; shrubby weeds.--Many of those mentioned are ORNAMENTAL PLANTS, especially Verbena; Vitex agnus castus is a S. European shrub. Lippia citriodora (S. Am.) etc., have strongly-scented leaves; the Teak tree (Tectona grandis) is one of the largest trees in East India, and has a very hard wood.

Avicennia is allied to this order; it inhabits the Mangrove swamps on tropical coasts. The endosperm emerges from the ovule, carrying the embryo with it; the embryo ultimately bursts the endosperm and lies free in the loculus of the fruit; this is then filled by the embryo with its large, green cotyledons, which are borne on an already hairy or rooted stem. The seedling thus developed falls from the tree, together with the fruit, and strikes root in the mud. One special cell of the endosperm at an earlier period becomes a highly-developed organ of suction, growing into a much-branched sac, very rich in protoplasm.

Order 4. =Labiatæ.= The special characteristics are: the square stem, the opposite leaves (without stipules), the inflorescences which are formed by two double unipared scorpioid cymes, the labiate corolla, the 4 didynamous stamens (the posterior being entirely suppressed) (Fig. 574), and the 4-partite schizocarp with nut-like fruitlets. The floral formula is S5, P5, A5 (the posterior stamen is generally absent), G2.

They are chiefly aromatic plants (herbs, shrubs, e.g. Lavender, or trees), volatile oil being formed in internal cells or in the glandular hairs, which cover all green parts. The stem is always more or less markedly square; the leaves are borne upon the flat sides, and are simple and penninerved, but vary in the other characters. The inflorescences are double unipared scorpioid cymes, which may be situated at some distance from one another in the axils of the foliage-leaves (Fig. 575 A), but frequently when the subtending leaves are bract-like, they are crowded into spike-like inflorescences (Lavandula, Mentha, Salvia, etc.), each of the so-called “whorls” (verticillaster, glomerulus) being a double unipared scorpioid cyme (Fig. 574). (Solitary flowers are found in e.g. Scutellaria, and Origanum). The calyx is strongly gamosepalous, 5-toothed, often bilabiate (Fig. 575 B). The corolla is strongly bilabiate (Figs. 575, 576, etc.), with 2 lobes in the upper lip and 3 lobes in the under lip (an approach to regularity occurs only when the upper lip is small, and thus resembles one lobe, as in Mentha (Fig. 578) and Lycopus, so that the corolla approaches the 4-merous corolla of Veronica and Plantago). The posterior stamen in the diagram (Fig. 574*) is entirely suppressed; in most of the genera the posterior lateral stamens are the smaller (Fig. 575 D), and are entirely suppressed in some (see below); in others, e.g. Nepeta, they are the longer. 2 stamens are found in Salvia, Rosmarinus, Lycopus, etc. The two halves of the anthers are often separated from one another, and are placed at an angle with each other. The gynœceum has 1 style with a bifid extremity (Fig. 575 C) bearing the stigma; the true bilocular ovary is divided by a false partition-wall into 4 loculi, each with 1 erect ovule (Fig. 575 H). These 4 loculi project so strongly that the ovary becomes deeply 4-lobed with the style situated in the centre of the lobes and at their base, “gynobasic” (Figs. 575, 579). A ring-like, often crenate, nectary surrounds the base of the ovary (Fig. 575 G, H). The embryo in this order, as in the Verbenaceæ, is directed downwards (Fig. 575 J) (it is directed upwards in the Boraginaceæ, which have an entirely similar fruit). Endosperm absent.

The 142 genera are mainly distinguished according to the form of the calyx and corolla, the number, direction, and length of the stamens, the forms of the nuts, etc.

=1.= AJUGEÆ, BUGLE GROUP. Calyx 10-nerved; the upper lip is small; 4 stamens. The ovary is not so strongly lobed as in the following group, so that it is most nearly allied to the Verbenaceæ. The nuts are reticulately wrinkled. Ajuga (Bugle) has a very small upper lip. The upper lip of Teucrium (Germander) is deeply cleft, and the two lobes are bent on their respective sides towards the under lip, which in consequence appears to be 5-lobed, and the upper lip to be wanting.

=2.= STACHYDEÆ, BETONY GROUP. The calyx is 5- or 10-nerved. The upper lip of the corolla is most frequently strongly arched or helmet-shaped; 4 stamens, the anterior pair the longer (Fig. 576).

=a.= A somewhat regular and 5–10-dentate calyx with projecting stamens.--Stachys (Betony, Woundwort); the lobes of the under lip are rounded off. The anterior filaments, after pollination, bend outwards. Betonica--Ballota (Horehound); the calyx is funnel-shaped, and has triangular, long, pointed, awn-like teeth.--Galeopsis (Hemp-nettle) has two conical protuberances on the under lip between the lateral and the central lobes. The anthers open by 2 unequal valves. Lamium (Dead-nettle, Fig. 576) has dentate, lateral lobes on the under lip. L. album (White Dead-nettle), L. rubrum, etc. Galeobdolon.--Leonurus; Phlomis.

=b.= Tubular, regular, often 10-toothed calyx and concealed stamens.--Marrubium vulgare (Fig. 577); 10 calyx-teeth, hooked at the apex; many almost spherical whorls of flowers in the axils of the foliage-leaves, at some distance from one another.--Sideritis.

=c.= Strongly bilabiate calyx, the lips closing together after flowering.--Scutellaria (Skull-cap); the two lips of the calyx are entire, the upper lip has a large spur, and drops off on the ripening of the fruit. The flowers are generally solitary and turned to one side.--Prunella (Heal-all); the calyx is compressed, its two lips are strongly dentate, the upper lips closing slightly round the under. The stamens have a tooth-like projection beneath the anthers.

=3.= NEPETEÆ, CATMINT GROUP. 13–15 nerves in the calyx; this deviates from the other groups in the posterior stamens being the longer. The upper lip is slightly arched. Nepeta (Catmint), also Glechoma (Ground Ivy), with regular, and Dracocephalum with irregular calyx.

=4.= SATUREIEÆ, MINT GROUP. The upper lip is flat, most frequently ovate, or almost spherical, and emarginate (Fig. 578). The calyx is most frequently 5–10-nerved. 4 stamens, the anterior being the longer; rarely, 2 stamens only.--Mentha (Mint, Fig. 578) has a regular, 5-dentate calyx, a small, almost regular, 4-partite corolla, and 4 erect stamens of nearly equal size. The verticillasters are many-flowered, and are often collected into cylindrical inflorescences. Herbs.--Lycopus (Gipsy-wort); corolla almost regular. 2 stamens, the posterior lateral ones are wanting. Preslia: 4-dentate calyx, 4-partite, regular corolla; 4 stamens of equal size.--Thymus (Thyme, Fig. 575) has a strongly bilabiate calyx, the throat being closed by a whorl of hairs (Fig. 575 B). The corolla is distinctly labiate. Under-shrubs, with small entire leaves; verticillasters few-flowered and separate.--Origanum (Marjoram); spike or capitate inflorescences with the flowers solitary in the axils of the rather large and distinctly 4-rowed (often slightly coloured) floral-leaves. Melissa. Calamintha. Clinopodium (Wild Basil). Satureia. Hyssopus (Hyssop); small, entire leaves; the verticillasters are situated unilaterally in a slender, spike-like inflorescence. Lavandula (Lavender); shrubs with verticillasters collected in cylindrical, long-stalked inflorescences; the calyx is tubular, has 13–15 nerves, the posterior tooth is much larger than the others. Stamens and style do not project. ~Coleus differs, among other characters, in having united filaments; the stamens and style are bent down and concealed in the boat-shaped under lip.~

=5.= MONARDEÆ, SALVIA GROUP. Only the 2 anterior stamens are developed.--Salvia (Fig. 579); calyx deeply bilabiate; the upper lip of the corolla is generally strongly compressed. Rudiments of the two lateral stamens are present. The connective in the two fertile stamens is long and filamentous, and bears at the upper end a normal half-anther, but at the lower one a barren, often broader portion, against which the insect is obliged to push its proboscis during its visits to the flowers, causing the pollen-bearing half-anther to be pressed down against its back. Floral-leaves often coloured.--Rosmarinus (Rosemary); a shrub with leathery linear leaves, with rolled back edge. A small tooth on the filament represents the barren half of the anther. Monarda.

The POLLINATION is generally effected by insects, especially bees; the under-lip is the landing-stage and the pollen is deposited on their backs. Cross-fertilisation is promoted by dichogamy; honey is secreted by an hypogynous disc and collected in the corolla-tube. Some genera are homogamous (Lamium, Galeopsis, etc.); others are dichogamous (protandrous); a few are gynodiœcious: ♀-and ☿-flowers in various relative sizes (Glechoma hederaceum, Thymus, Salvia pratensis, and others). The entrance of uninvited guests to the honey is often rendered difficult by whorls of hairs, etc. In numerous instances the upper lip protects the pollen from rain. Cleistogamy is found e.g. in Lamium amplexicaule.

2,700 species; distributed over the entire globe, but the greater number in Mediterranean countries (especially in the Eastern regions), where many are shrub-like.--Poisonous and acrid properties are absent. On account of their volatile oils they are principally used as condiments, for perfumery and in medicine (the officinal parts are therefore nearly always “folia” and “herba,” in Lavandula the flowers, and the volatile oils extracted from them). Such are:Mentha piperita [+] (Peppermint)--menthol is obtained from this species and from M. arvensis--M. viridis [+] (Spearmint), M. crispa (Curly-mint), Thymus vulgaris (Garden Thyme), Melissa officinalis (S. Eur.), Hyssopus officinalis (Hyssop, S. Eur.), Origanum majorana (Marjoram, from the Mediterranean), O. vulgare (Wild Marjoram), creticum, smyrnæum, etc., Salvia officinalis (S. Eur.), Rosmarinus officinalis (oil of Rosemary, S. Eur.), Lavandula vera [+] (oil of Lavender, S. Eur.). Also: Satureia hortensis (S. Eur.), Ocimum basilicum (E. India), Pogostemon patchouli (E. India), etc.--As ornamental plants, e.g. Monarda, Plectranthus, and Coleus (foliage-plants, often with red stems and leaves), Stachys lanata (white, woolly), Phlomis, Salvia-species, Perilla, etc.

Order 5. =Selaginaceæ.= 130 species; small, most frequently heath-like shrubs or herbs, mainly from S. Africa. They differ from the other Nuculiferæ especially in the bilocular, transversely-placed anthers of the 4 stamens (2 stamens divided as far as the base (?)). The ovary has 2, or by suppression only 1 loculus, each with 1 ovule, and the fruit is a schizocarp dividing into two, or is a 1-seeded nut. Radicle turned upwards.--A few are ornamental plants (Selago, Hebenstreitia).