Part 50

=D.= DRACÆNEÆ. Fruit in some a berry, in others a capsule. The stem of DRACÆNA, when old, has the appearance of being dichotomously branched; it has the power of increase in thickness, and may become enormously thick. The Dragon-tree of Teneriffe, measured by Humboldt, attained a circumference of 14 m. and a height of 22 m.; the leaves are large, linear or linear-lanceolate.--Cordyline (East Asia), various species in gardens and greenhouses (Yucca is closely allied). Astelia.

POLLINATION. Paris quadrifolia and Convallaria majalis have no honey, and are chiefly visited by pollen-collecting bees (in the absence of insect visits self-pollination takes place); Polygonatum multiflorum has honey secreted by septal glands and protected by the base of the tubular perianth; it is pollinated by humble-bees, etc. Asparagus officinalis has small, polygamous, greenish, honey-bearing flowers; the ♂-flower is almost twice as large as the ♀; both have rudiments of the opposite sex.

About 555 species; especially from N. America, Europe, and Central Asia.

OFFICINAL: “Dragons’-blood,” a red resinous juice from the stem of Dracæna and the roots of some Central American species of Smilax. The tuberous stems of the Eastern Asiatic Smilax glabra are officinal. The flowers of Convallaria majalis have been lately used as a substitute for Digitalis. Pungent, poisonous properties are possessed by Paris. None of the species are used as food, except the young annual shoots of Asparagus officinalis, a shore-plant which is used as a vegetable.

Order 4. =Pontederiaceæ.= Flowers generally zygomorphic, hypogynous, ☿, with handsome, white or violet, petaloid perianth which forms a tube at its base. The stamens are inserted at different heights in the perianth-tube, and are reduced to three (in Heteranthera seldom to one). In some the ovary is trilocular with ∞ ovules (Eichhornia), in others reduced to one loculus with one ovule (Pontederia). Fruit a capsule or nut. Embryo as long as the abundant, mealy endosperm.--Tropical water-plants (22 species) with peculiar sympodial branching, nearly the same as in Zostera. Spikes without floral-leaves. Many intercellular spaces in the stem and leaf.--In greenhouses: Eichhornia azurea, E. crassipes (both from tropical and sub-tropical S. America); the latter has swollen petioles which serve as floats and enable it to float freely on the water, sending down its roots into the mud. Heteranthera reniformis, H. zosterifolia. Pontederia cordata.

Order 5. =Amaryllidaceæ (Narcissi).= The flower is epigynous, otherwise exactly the same as in the Liliaceæ (6 stamens). The majority, like these, are also perennial herbs with bulbs and scapes. The fruit and the other characters as in the Liliaceæ. The external appearance is, however, very different.

=A.= AMARYLLEÆ have bulbs and the leaves generally arranged in two rows; the flowers are borne singly or in umbel-like inflorescences on lateral scapes, while the main axis of the bulb is unlimited. Beneath the inflorescence is an involucre (Fig. 309).--Galanthus, Snowdrop, has a polyphyllous perianth without corona; the three inner perianth-leaves are emarginate and shorter than the outer; the anthers dehisce apically. ~Leucojum differs in having the perianth-leaves equal in length.--Amaryllis has a funnel-shaped perianth, entirely or nearly polyphyllous, but somewhat zygomorphic. Crinum; Hæmanthus; Clivia.~--Narcissus has a tubular corona, a ligular structure arising from the perianth-tube exterior to the outer stamens. ~In Pancratium (Fig. 309) the corona is united with the filaments which appear to spring from its edge. Eucharis amazonica.~

=B.= HYPOXIDEÆ. The leaves, which are grass-like, dry, folded, and in some hairy, spring from a rhizome, generally with a divergence of 1/3. Flowers small, perianth polyphyllous, persistent, on which account perhaps the Hypoxideæ may be considered as the least altered type. The chief characteristic is that the embryo is separated from the hilum. Hypoxis; Curculigo (C. recurvata, a favourite ornamental plant; S.E. Asia).

=C.= ALSTRŒMERIEÆ. (Alstrœmeria, Bomarea); stems long, leafy, often climbing.

=D.= VELLOSIEÆ (Vellosia, Barbacenia); stem woody, usually dichotomously branched, with terminal, single flowers; it bears numerous aerial roots which pierce the leaves and surround the stem. Stamens often (by splitting) 6–18. High table-lands of S. America and S. Africa.

=E.= AGAVEÆ. Very similar to the Bromeliaceæ both in their distribution (nearly all American) and in external appearance. They appear as gigantic bulbous plants with perennial, aerial, generally short stem, and perennial, large, lanceolate or linear, stiff, thick, and often thorny leaves, which form a large rosette; after the course of several (8–20) years the terminal inflorescence is developed, which is 10–12 m. high, paniculate, and freely branched. Before the inflorescence expands, a large quantity of sugar-containing sap is collected from A. americana by removing the terminal bud; this on distillation yields “pulque,” the national drink of Mexico. After flowering the entire shoot dies, but the subterranean lateral shoots survive and reproduce the plant.--Agave americana, etc.; Fourcroya; Polianthes tuberosa (Tuberose; Central America).

DISTRIBUTION. The 650 species are chiefly natives of S. Africa and S. America. Clivia, Hæmanthus, Amaryllis are from the Cape; Narcissus from S. Europe, whence many species have been introduced; Galanthus and Leucojum are especially from S. and Central Europe, and from the Caucasus.

USES, few, except as ornamental plants: Galanthus nivalis; Leucojum; Narcissus pseudonarcissus, N. poeticus, N. jonquilla, N. tazetta, etc.; Amaryllis, Alstrœmeria, Eucharis, Crinum, Vallota, etc. The vascular bundles of the various species of Agave (Agave rigida, var. sisalana, sisal hemp,) are used for cordage, etc.

Order 6. =Bromeliaceæ.= The flowers are hypogynous, epigynous or semi-epigynous; the perianth is divided into calyx and corolla; stamens 6. The fruit is a capsule or berry with many seeds. Endosperm mealy, embryo small, at the edge of the endosperm, but not enclosed by it.

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, 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.