Orchideae
A very large order of monocotyle-donous plants, and one of the most natural families of the vegetable kingdom. Herbaceous terrestrial perennials, with tuberous or fascicled roots; epiphytes (with or without pseudo-bulbs), found generally growing on the trunks of trees, to which they attach themselves by their long adventitious roots; or saprophytes. Flowers solitary, spicate, racemose or paniculate; perianth superior, irregular, of six coloured segments, the three outer (the sepals) nearly similar, free, or the two lower ones connate (Cypripedium), or all three coherent (Masdevallia); the inner lateral (the petals) similar; the third inner segment (the lip) originally superior, but afterwards becoming inferior by the twisting of the pedicel, dissimilar, usually larger, extremely varied in shape and colouring, frequently spurred (Angraecum, &c.) or pouched (Cypripedium); stamens united with the style into a column, usually one opposite the upper sepal, sometimes two (Cypripedium) opposite the two lateral petals; anther two-celled (or one-celled by absorption of the septum), or four-celled by more or less perfect secondary septa; pollen agglomerated into two, four, or eight, pear-shaped, usually stalked masses (pollinia), lodged in the membranous pockets of the anther, and composed of grains, usually collected by fours into numerous groups, cohering by means of elastic filaments, or gathered round a cellular axis; grains sub-pulverulent, easily separable, or agglutinated into a solid, compact, waxy tissue; pollenmasses sometimes free, usually fixed, either directly or by means of a pedicel (caudicle), to a viscous gland (retinaculum), which may be exposed, or inclosed in one or two pouches; ovary inferior, often long, and twisted, one-celled (more rarely three-celled), trigonous; style often terminating in a beak (rostellum) at the base of the anther, or between its cells; stigma a viscid surface facing the lip, beneath the rostellum; seeds innumerable, very minute, fusiform; testa very lax-reticulate and albuminate. Leaves sheathing at the base, glabrous, rarely velvety (Eria), very firm in texture (Cattleya), or membranous (Liparis), cylindric (Brassavola), linear (Isochilus), or linear-lanceolate, usually entire or emarginate, as in Vanda, or some Angraecums, fan-shaped (Pogonia) or heart-shaped (Listera); nerves parallel, rarely reticulate (Dossinia, &c.), now and then developing buds on their surfaces, as in some Spiranthes and Malaxis. Stem or scape usually simple, cylindric or angular, often leafless. According to the authors of the " Genera Plantarum," there are 334 genera and about 5000 species; in that work, these are divided into five tribes, the principal distinguishing characteristics of each being here given. TRIBE I. EPIDENDREAE. Anther one, dorsal, operculate, usually incumbent, with the cells distinct and parallel; pollinia waxy, in one or two series, parallel, two to four in each series (one to four in each cell), free, or joined in each cell by a little viscous substance, or a granular appendage, very rarely attached to the rostellum. This tribe contains eighty-eight genera, and is divided, by Bentham and Hooker, into nine sub-tribes; it is represented, in both hemispheres, by both terrestrial and epiphytal genera, and includes some of the most beautiful garden plants: Calanthe, Cattleya, Dendrobium, Laelia.
TRIBE II. VANDEAE. Anther one, dorsal, operculate, incumbent, or applied to the rostellum; cells most frequently confluent; pollinia waxy, usually two or four, applied to each other in pairs, posterior and anterior. Vandeae is divided into nine sub-tribes, and contains 129 genera, the great majority being epiphytes. This group is represented almost in equal numbers in tropical Asia and America; there are many members in Madagascar, few in Africa, and very few beyond the tropics. Familiar examples are: Aerides, Odontoglossum, Oncidium, Phalaenopsis, and Vanda.
TRIBE III. NEOTTIEAE. Anther one, posterior, operculate, or erect and persistent; cells distinct, parallel; pollinia granular, powdery, or sectile. Stems without pseudo-bulbs. There are six sub-tribes of Neottieae, and eighty-one genera, nearly all of which are rhizomatose terrestrial plants--Vanilla is sub-epiphytic. They have erect, simple stems, which are leafy at the base, or are quite leafless. Neottieae are represented in both hemispheres, a considerable number being extra-tropical. Examples are: Anaectochilus, Pogonia, Sobralia, Vanilla.
TRIBE IV. OPHRYDEAE. Anther one, posterior, erect, prostrate, or reflexed, with parallel or divergent, distinct cells adnate to the clinandrium, and often continuous with the rostellum; pollinia granular, produced into a caudicle in each cell. There are thirty-two genera of Ophrydeae, divided into four sub-tribes. All are terrestrial plants, with tuberous roots, the largest number of genera being found in South Africa, and but few in the tropics. The species are, perhaps, most numerous in the Mediterranean region. Examples are: Aceras, Disa, Ophrys, Orchis.
TRIBE V. CYPRIPEDIEAE. Anthers two, lateral; the rostellum prolonged into a shield between the anthers; pollen powdery. This tribe contains but four genera, only two of which, Cypripedium and Selenepedium, are in cultivation; the first is widely distributed over the temperate and tropical regions of both hemispheres, the latter being confined to the mountainous regions of South America. The two genera not in cultivation, Apostasia and Neuwiedia, are respectively limited to tropical Asia, and Australia and tropical Asia. All four are terrestrial herbs.
Linnaeus, in the middle of last century, only know about a dozen exotic orchids, whereas now, probably, half the known species are, or have been, in cultivation in this country. By far the larger number inhabit tropical forests; they become less plentiful in temperate regions, and are almost absent from very cold ones--perhaps not more than two or three enter the Arctic Circle. They vary exceedingly in size; the Javan Galeola altissima, which has been said to be the largest known orchid, attains a length of more than 100ft.; but a Vanilla has been seen under cultivation with a stem even longer than this. Drymoda picta is one of the smallest of Orchids; it has a dull green, small, disk-like pseudo-bulb, from which springs a minute and very deciduous leaf. Angraecum funale, and some other species of the same genus, as well as some of the African Vanillas, are quite leafless, and depend upon the chlorophyll present in the strap-like roots of the first-named, and in the long stems of the latter genus.
Scarcely any natural order of plants is more free from fungoid attacks than are Orchideae; for what is known about the fungi which have been observed on cultivated Orchids, the reader is referred to a paper by Mr. Worthington G. Smith, in the "Gardeners' Chronicle" (n. s., xxiv. p. 693). This volume also contains an account, by Professor Westwood, of the various phytophagous insects which have been found on imported Orchids. Among some of the other important results of the Orchid Conference of 1885, may be specially mentioned the paper on the Hybridisation of Orchids, by Mr. H. J. Veitch. This also is published in the "Gardeners' Chronicle" (n. s., xxiv. p. 628), and is illustrated by figures of seeds and seedlings of Cypripedium, Dendrobium, and Phalaenopsis.
"Of the few orchids which are of use to man, the Vanillas (Vanilla claviculata, planifolia, &c.) hold the first rank. They are sarmentose plants, natives of the hot and damp regions of Mexico, Colombia, and Guiana [and tropical Africa]. Their fruit is a fleshy, long capsule, and the black, globose seeds are enveloped in a special tissue, which secretes a balsamic oil; if kept in a dry place, the capsule becomes covered with pointed and brilliant crystals of benzoic acid, and imparts its delicious perfume to various delicate dishes, chocolates, liqueurs, &c. The Faham (Angraecum fragrans) is a native of Bourbon; its leaves, known as Bourbon Tea, taste of Bitter Almonds, and smell like Tonquin Beans they are used to stimulate digestion, and in pulmonary consumption. Salep, which is imported from Asia Minor and Persia, is produced by the tubers of several species of Orchis, which are equally natives of Europe (O. mascula, Morio, militaris, maculata, &c.). Salep contains, in a small volume, an abundance of nutritive starch, associated with a peculiar gum, analogous to Bassorine; it was formerly considered a powerful analeptic; it is now used as a sweet, scented jelly, or mixed with chocolate. The root of Helleborine (Epipactis latifolia) is employed for arthritic pains; those of Himantoglossum hircinum, Spiranthes autumnalis, and Platanthera bifolia, are reputed to be aphrodisiac. The flowers of Gymnadenia conopsea are administered for dysentery; and, in North America, the tubers of Arethusa bulbosa are used to stimulate indolent tumours, and in toothache. The root of Spiranthes diuretica is renowned in Chili. The rhizome of Cypripedium pubescens replaces the Valerian as an antispasmodic, in the estimation of the Anglo-Americans" (Decaisne and Le Maout).