Part 29

Perennial herbs with a very _characteristic appearance_ (Fig. 310); the stem is most often short, thick, and crowned by a _rosette_ of many leaves, which are long, often very narrow, _leathery_, stiff, and with a _spiny_ edge; they are usually channeled, completely closing round each other, with their edges forming a tightly closed hollow, in which generally water is collected (this among other things insulates the inflorescence and thus prevents the access of creeping insects, such as ants). The presence of numerous stellate, water-containing hairs often gives the leaves a grey appearance, and the layers of cells beneath the upper epidermis of the lamina form an “aqueous tissue,” which serves as a protection against the rays of the sun and regulates the evaporation. The stomata are often situated in furrows on the underside of the leaf, and hence cause a striped appearance. They _are all American_ (525 species), especially from S. America, where they live partly as epiphytes _on trees_, partly in the _clefts of rocks_, often on the steepest slopes, to which they firmly attach themselves by aerial roots; some are terrestrial. The stem is seldom tree-like or many metres in height (_Puya_, in Chili; _Hechtia_, in Mexico). _The inflorescence_ is a terminal spike, raceme, or panicle, often with large and brightly-coloured floral-leaves. The flowers are without scent. The seeds, in the species whose fruit is a capsule, are often provided with wings (hairs, expansions, etc).--_Ananassa sativa_, Pine-apple (W. Indies, Central America) is cultivated for the sake of its juicy, aromatic fruits, which coalesce with their fleshy bracts and form a large spike-like fruit-cluster (multiple-fruits,[29] Fig. 311) bearing on its apex a leafy shoot, which may be used as a cutting. Seeds very rarely developed.--_Tillandsia_ (_T. usneoides_ is a filamentous, richly branched, rootless epiphyte hanging in masses from trees; Trop. Am.), _Aechmea_, _Billbergia_, _Pitcairnia_, etc.

USES. The leaves of the Pine-apple, in its native country, are used for the manufacture of cloth.

Order 7. =Hæmodoraceæ.= 120 species; in all parts of the world except Europe; perennial, often tomentose and resembling the Bromeliaceæ, Iridaceæ and Amaryllidaceæ. _Hæmodorum_ (Australia).--To this order belong _Ophiopogon_, _Peliosanthes_, _Sanseviera_, and others.

Order 8. The =Iridaceæ= have _epigynous_, hermaphrodite flowers with petaloid perianth as in the Amaryllidaceæ, but the _interior whorl of stamens is entirely suppressed_, and the 3 developed _outer_ stamens have _extrorse_ anthers (Fig. 279); there is 1 style with 3 large, generally _more or less leaf-like branches bearing the stigmas_. Ovary and capsule as in the Amaryllidaceæ and Liliaceæ.--Perennial herbs; _bulbs are rarely found_, but horizontal rhizomes, corms, etc., take their place. The leaves are (except _Crocus_) as in the _Iris_, _two-rowed_, _equitant_ and _sword-like_. Flowers or inflorescences terminal.

The _Iris_ (Flag) has a horizontal rhizome. The flowers are borne in the leaf-axils in fan-like inflorescences (rhipidium). The branches of the style are large and _petaloid_; on their under surface may be seen a small projecting shelf (Fig. 312 _a_) having on its upper surface the stigmatic hairs. Beneath the branches of the style are 3 well protected stamens, and immediately outside these the external perianth-leaves. ~The honey is secreted in the perianth-tube, and the insects, endeavouring to obtain it through the narrow passages at the base of the stamens, settle upon the outer perianth-leaves, which are bent backwards and often very hairy along their central line. The insects then rub their backs on the anthers just above them, beneath the branches of the style; they readily deposit the pollen on the stigma of another flower as they enter it, but cannot do so in withdrawing, since the stigma is pushed back, and self-fertilisation is thus avoided. The stylar branches lie close to the outer perianth-leaves, which are just beneath them, or separated by a distance of only 6–10 mm.; the first form of flower is adapted for _Rhingia rostrata_, the latter for bees~.--_Crocus_ has vertical, _tuberous_, underground stems surrounded by the leaf-sheaths (corms), and terminal flowers; the linear leaves _are not equitant_, but have two longitudinal furrows on the under side. The perianth is gamophyllous and funnel-shaped. The stylar branches (stigmas) are fleshy, _rolled together in the shape of a horn_, and split along the edge.--_Gladiolus_ has corms like the _Crocus_; spikes with slightly zygomorphic, almost bilabiate flowers, most frequently turning to one side. Position of the leaves as in the Iris.--~_Diplarrhena_ has 2 fertile and 1 barren stamen; _Hermodactylus_ has a unilocular ovary with 3 parietal placentæ. _Cypella_ and _Tigridia_ have bulbs.~

770 species; chiefly in the countries round the Mediterranean, and in Africa, especially the Cape (_Gladiolus_, _Ferraria_, _Moræa_, _Galaxia_, _Sparaxis_, _Antholyza_, _Tritonia_, _Ixia_, etc.), Australia and Tropical America (_Sisyrinchium_, _Tigridia_, _Cipura_, _Cypella_, etc). A great number are ornamental plants: the cultivated _Crocus_-species are from the South of Europe and Asia; _Gladiolus communis_ from S. Europe; the other species principally from S. Africa. The native species of _Iris_ are _I. pseudacorus_ (yellow) and _I. fœtidissima_.

OFFICINAL: the stigmas of _Crocus sativus_ (Oriental, cultivated in France, Spain, Italy, and Austria), used as a colouring matter, saffron; the rhizomes of the S. European _Iris florentina_, _pallida_, and _germanica_ (“Orris-root”).

Order 9. =Dioscoreaceæ.= Perennial herbs with fleshy, often very large _tuberous rhizomes_ (or roots); _twining_ stems; leaves stalked, often arrow- or heart-shaped, lobed, _palminerved_ and _finely reticulate_ as in the Dicotyledons (Fig. 313). The flower is _diclinous_ (most frequently _diœcious_), regular, _epigynous_, _small_, and of a _greenish colour_, but otherwise typical (Pr3 + 3, and A3 + 3, or G3); in most instances 2 ovules are placed one above the other in each loculus. The inflorescence is a _spike_ or _raceme_, sometimes richly branched and paniculate.--The order approaches most nearly to the Amaryllidaceæ.

_Tamus_ (Bryony) has a berry, _Dioscorea_ (Yam) a thin-walled, 3-edged or 3-winged capsule (Fig. 313). Both have subterranean or aerial tubers; the Yam very often also developes tubers in the axils of the foliage-leaves; tuberous roots are said to occur in _D. batatas_. The tubers of many species of Yams (_D. batatas_ from China and Japan, _D. alata_, South Sea Islands and India, _D. bulbifera_) are a very important source of food in the Tropics, especially the first-named.--_Testudinaria_; _Rajania_.--~The tuberous stem of _Tamus communis_ and _Testudinaria elephantipes_, and some species of _Dioscorea_ is formed from one single internode (epicotyl), and the aerial shoots are developed from adventitious buds; in _T. elephantipes_ the stem is aerial, and covered with thick scales of cork, regularly arranged, and separated by grooves.~

Tropical order (167 species); 2 species (_Tamus communis_ and _Borderea pyrenaica_) in Europe.

Family 6. =Scitamineæ.=

The flowers belong to the ordinary monocotyledonous type. They are hermaphrodite, _epigynous_, and have either a petaloid perianth, or calyx and corolla; they are, however, _zygomorphic_ or _unsymmetrical_, and of the stamens most frequently only one is _completely developed_, the others being generally represented by petaloid staminodes. The ovary has 3 loculi, more rarely it is unilocular with the suppression of 2 loculi. Endosperm is absent (except _Zingiberaceæ_); but, on the other hand, there is a _large perisperm_. To this family belong large, glabrous, especially _perennial herbs_ with rhizomes; leaves large, distinctly divided into sheath, stalk, and blade, the latter being more or less elliptical or lanceolate, entire, with pinnate venation, and always with a very _well-pronounced midrib_, gradually tapering towards the apex, and giving off numerous branches, which run outwards, towards the margin, at a larger or smaller angle; these _lateral veins_ are closely packed, and parallel, but with only weak, connecting branches between them; the leaves, therefore, are easily torn pinnately (Figs. 314, 317). The leaf-sheaths close tightly round each other and form a false stem.

This very natural family comprises orders closely connected with each other, but is not itself nearly allied to any other family. First in the series stands:--

Order 1. =Musaceæ.= The _petaloid_ perianth is strongly zygomorphic, the anterior leaf being very large (a kind of “labellum”), the posterior one small; only the posterior stamen is wanting, or is rudimentary, the other five are developed, and have quadrilocular anthers; ovary, 3-locular. Seed with straight embryo in mealy perisperm.

The best-known genus is _Musa_, the Banana (Fig. 314). From the short rhizome arise enormously large, spirally-placed leaves, whose sheaths envelope one another, and form an apparently aerial stem, several metres in height. The inflorescence is a terminal _spike_ with floral-leaves placed spirally, and sometimes magnificently coloured; in the axils of each of these several flowers are situated in two transverse rows (accessory buds); the lowest flowers in the inflorescence are ♀, the central ones ☿, the upper ones ♂, so that fruits are only found in the lower region of the inflorescence, the remaining portion persisting as a naked axis after the floral-leaves and flowers have fallen off; the inflorescence terminates in an ovoid bud formed by the flowers which have not yet opened (Fig. 314, the left-hand figure). The perianth-leaves are united (except the posterior one). The fruit (known as a “Banana”) is a _berry_, having the form of a smooth, short, three-cornered Cucumber (as much as 30 cm. in length); inside the tough skin is found a farinaceous, aromatic pulp. No seed is developed in the cultivated species.--~Several _Musa_-species are cultivated in the Tropics for the sake of the fruit (_M. paradisiaca_, _M. sapientum_); for the fibrovascular bundles, _M. textilis_ (Manilla Hemp).--Their home is, no doubt, the Tropics of the Old World; they were introduced into America before the arrival of Europeans. _Musa ensete_ has dry, leathery fruits; an ornamental plant.~

In _Musa_ the barren, posterior stamen belongs to the inner whorl; and also in _Strelitzia_ and _Ravenala_; the latter may have all 6 stamens developed. In _Heliconia_, on the contrary, it belongs to the outer whorl; in _Heliconia_ the perianth-leaves are differently arranged, and there is only one ovule in each loculus. The three latter genera have dry fruits and leaves arranged in two rows. In the “Travellers’ Palm” (_Ravenala madagascariensis_) the foliage-leaves form an enormous fan.--Tropical; about 50 species.

The order may be divided as follows:--1. Museæ: _Musa_, _Ravenala_, _Strelitzia_ in the Old World. 2. Heliconiæ: _Heliconia_ in the New World.

Order 2. =Zingiberaceæ.= Perianth most frequently divided into _calyx_ and _corolla_. Calyx gamosepalous. Only 1 _fertile stamen_ (the posterior, Fig. 315, belonging to the inner whorl) with quadrilocular anther, which encloses the style in a furrow; the 2 stamens in the outer whorl are staminodes, the median one (the anterior) is wanting. The 2 lateral staminodes of the inner whorl form the “labellum” (Fig. 315 _lab_), which usually is the largest segment of the flower, and is often bilobed. Ovules many. The fruit in some is a leathery, 3-valved capsule, with loculicidal dehiscence; in others it is more or less berry-like and indehiscent, or irregularly dehiscent. Straight embryo.--The aerial stem is seldom developed to any extent, and the inflorescences, which are (compound) spikes or racemes, often with coloured floral-leaves, spring in some (_e.g. Zingiber officinale_) directly from the rhizome. The leaves are arranged in two rows.--The ovary in a few instances (_Globba_ and others) is unilocular, with 3 parietal placentæ.

They are perennial herbs with fleshy and tuberous rhizomes, which are used as condiments and in medicine on account of their pungent and aromatic properties and also for starch, dyes, etc. OFFICINAL: _rhizomes_ of _Zingiber officinale_ (Ginger, unknown wild, but cultivated generally in the Tropics), of _Curcuma longa_ (Turmeric, a dye, E. India) and _C. zedoaria_, of _C. angustifolia_ and others (as E. India Arrowroot), of _Alpinia officinarum_, China (galangal). “Preserved Ginger” from _Alpinia galanga_. Similar aromatic materials (volatile oils) are present also, for example, in _the fruits_; Cardamom fruits and seeds (from _Elettaria cardamomum_, China, seldom from _E. major_).

315 species; Tropics, preponderating in the Eastern Hemisphere, India, and especially S. Asia, whence all the aromatic species originate; they are now commonly cultivated in the Tropics. Some are ornamental plants in greenhouses, _e.g._ _Hedychium_, _Costus_, etc. _Globba_ (with axillary buds in the inflorescence, as in _Ficaria_), _Renealmia_, _Kæmpferia_.

Order 3. =Cannaceæ.= American herbs without aromatic properties. Flowers asymmetric (Fig. 316). Calyx polysepalous. The stamens are _petaloid_ (Fig. 316 _st_) and barren with the exception of one (the posterior), which bears on one of its _edges_ a bilocular anther; another, which is especially large and coloured, is termed the _labellum_. The style is compressed and leaf-like, with a small stigma at the apex. Ovules numerous in the 3 loculi. The capsule is furnished with warts or soft prickles. _Embryo straight._

_Canna_ (30 species; Trop. Am.). The inflorescence is a terminal spike with 2-flowered unipared scorpioid cymes in the axils of the floral-leaves. Ornamental plants: _Canna indica_, etc.

The diagram of the andrœcium of the Cannaceæ and Marantaceæ may be represented in the following manner (calyx, corolla and gynœceum being omitted):--

CANNACEÆ. MARANTACEÆ.

_w_ _w_ _w_ _w_ _st_ _st_ _w_ _lab_ _wi_ _c_ * *

_w_ The lateral staminodes, “wings;” _st_ fertile stamen; * the suppressed stamen; _lab_ labellum; _c_ hood; _wi_ inner-wing.

The labellum of the Cannaceæ corresponds with the hood of the Marantaceæ and not with the labellum of the Zingiberaceæ.

Order 4. =Marantaceæ.= The flower is asymmetrical. Only 1 or 2 of the 3 stamens in the outer whorl are present as staminodes; in the inner whorl 2 are petaloid and of the sixth stamen one-half is developed as a staminode and the other half bears a bilocular anther. One ovule only in each loculus. The style is strongly curved and at first enclosed in one of the staminodes (hood) of the inner whorl; later on it springs elastically forward towards the other staminode (inner-wing) of the same whorl. The stigma is very oblique or 2-lipped. Two of the three loculi of the ovary, in some (_Maranta_, _Thalia_) become small and empty. Embryo _curved_. Leaves in two rows, with sheath, stalk, and blade (Fig. 317); at the base of the last is a _characteristic swelling_ (_articulus_).--~_Phrynium_, _Calathea_, _Stromanthe_, _Ctenanthe_, _Saranthe_, etc. About 150 species; tropical, especially America. The starch of the rhizome of _Maranta arundinacea_ is OFFICINAL, “West Indian Arrowroot.”~

Family 7. =Gynandræ.=

The flowers are hermaphrodite and constructed on the ordinary 3-merous, pentacyclic type with petaloid, _epigynous, strongly zygomorphic_ perianth, and generally _one-stamened_ by the suppression of the other 5 stamens. The family has derived its name from the fact that the stamen is united with the style into a “_stylar column_” (except _Burmanniaceæ_). All are herbs; many grow as epiphytes on other plants.

This family and the Scitamineæ occupy correspondingly high positions among the Monocotyledons; these two families may therefore be placed close together, although one cannot be derived from the other. The first of the two orders is very small, but the second is very rich in species. The Apostasieæ are best classed with the Orchidaceæ and have no independent place.

Order 1. =Burmanniaceæ.= This order forms a transitional link between the Gynandræ and the epigynous Liliifloræ (_Amaryllidaceæ_), in having a 6-leaved perianth, and 6–8 stamens; but some have a labiate perianth (the median perianth-leaf of the _outer_ whorl being very large). The ovary is most frequently unilocular with three parietal placentæ; but in some it is 3-locular with axile placentation. Capsule. Seeds ∞, small, with _endosperm_. The relationship to the Orchidaceæ is shown especially in the very imperfectly developed embryo and in the ovary. Small, tropical herbs (59 species); some are saprophytes.

Order 2. =Orchidaceæ.= The epigynous, petaloid perianth is strongly zygomorphic in having the _posterior_ leaf of the interior whorl, the _lip_ (labellum), differing from all the other leaves in form, size, and colour (except _Apostasieæ_); the position of the labellum is very frequently reversed, being turned _forwards and downwards_ by the twisting of the ovary (Fig. 318 _A_). _Only_ 1 of the stamens--the anterior of the external whorl--is developed and bears an anther (by the twisting of the ovary it is turned posteriorly and upwards); the others are entirely wanting (indicated by * in Fig. 318 _A_) or present as staminodes (Fig. 318 _A_, δ δ) (except _Apostasieæ_, _Cypripedileæ_); the filaments are united with the style to form a column (Fig. 318 _B_), the _stylar-column_[30] (_gynostemium_), and the anther (_a_) is thus placed on its apex and exactly behind or over the stigma (_s_). The anther is 4-locular; the pollen-grains do not separate (except _Apostasieæ_, _Cypripedileæ_) but remain united either in tetrads or in masses, which correspond to a pollen-mother-cell (Fig. 320 _C_, _D_, _E_); or the pollen-grains, formed in each of the two anther-halves, remain united and form one or a few wax-like masses (pollen-masses, pollinia). The 3 carpels form a _unilocular ovary_ with 3 parietal, deeply bifid placentæ (except _Apostasieæ_, _Selenipedilum_). Only the two lateral carpels are prolonged and developed into the stigma (Fig. 318 _B_, _s_), while the one lying in the median line, which is situated just within the anther (Fig. 318 _A_), becomes either rudimentary or developed into the “_rostellum_” (“a small beak”), on which the sticky bodies (_glandulæ_) arise; by aid of these the heavy, connected pollen-masses may be glued to the insects which visit the flower, and pollination is thus secured (in _Apostasieæ_ and _Cypripedileæ_ the 3 carpels each contribute to the formation of the stigma). The fruit is a _capsule_ which most often dehisces _by 6 valves_, 3 of which are broader and bear the placentæ, and 3 alternating with them are narrower and barren (except _Vanilla_). The very numerous and exceedingly small seeds have _no endosperm_, and have a somewhat _spherical embryo without any trace of external organs_. The testa is membranous and loose.

The Orchids are _all perennial herbs_ with diverse habits and varying morphological structure (see the genera); the leaves are scattered, of the usual Liliaceous form, and the inflorescences in all cases are _racemes or spikes_ (sometimes branched), with subtending bracts, but without bracteoles.

The forms which are the least modified are described first.

=1.= APOSTASIEÆ. The perianth-leaves are almost alike and free. The column is straight, with 3 equally-developed stigmas. _Neuwiedia_ has 3 perfect stamens (1 median of the outer whorl, and 2 lateral of the inner whorl); _Apostasia_ has only 2 perfect (inner lateral) and one barren (the median of the outer whorl), which however may be entirely wanting. The 3 _posterior_ stamens are entirely suppressed. The pollen is powdery. The ovary is 3-locular with axile placenta. 7 species (Tropical East India, Australia).

=2.= CYPRIPEDILEÆ.[31] The flower is strongly zygomorphic with a large boat-shaped labellum. There are two perfect stamens belonging to the _inner_ whorl, and the median anterior (later on the posterior) stamen of the outer whorl is transformed into a large, barren, shield-shaped body (Fig. 319). _Selenipedilum_ has a 3-locular ovary, but _Cypripedilum_ (Ladies’-slipper) has a unilocular ovary with 3 parietal placentæ--the typical structure for the Orchids. The pollen-grains are _separate_ (not in tetrads) and all the 3 lobes of the stigma are constructed to receive them. This group is therefore, next to the Apostasieæ, the least modified among the Orchids; in all the following groups, one of the lobes of the stigma is differently developed from the others, and there is only one stamen.--Terrestial Orchids.--~The pollination of _C. calceolus_ is effected by the forcible entrance of insects into the boat-shaped labellum (Fig. 319 _p’_) at _i_, and their escape at _ex_ (in 2) where the anthers are situated; in this way the stigmas will first be touched and then the anthers. The pollen-grains are surrounded by a sticky mass in order that they may adhere to the insects.~