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Orchids. A vast assemblage of herbaceous plants, mostly with unusual and interesting flowers, of which about 15,000 species are at present known. This number is being augmented yearly as the regions which they inhabit become more accessible to collectors. A single collection in New Guinea in 1907 to 1909 brought to light 1,102 new species,—an indication of the number of new forms still to be expected from little-explored regions. Since the first edition of the "Cyclopedia of American Horticulture" was published, the number of known species has been increased by about 5,000. Probably the species now outnumber those of the great, family Compositae.
Although widely distributed, the orchids are seldom abundant in any place as to individual plants. They are mostly inhabitants of special or particular places. Orchids are also highly specialized in structure, particularly in character of flowers, in this differing widely from the broadly generalized structure of the Compositae.
These very special plants, with marvelous range of form and color, have naturally excited the greatest interest on the part of cultivators, and great collections have grown up. To a large extent, these collections have been renewed from fresh importations from the wild, but the recent discoveries of symbiotic relations in germination, as well as better understanding of cultural requirements, will constantly increase the domestic supply. In the culture of a wide range of orchids the gardener exhibits his mastery of the arts of cultivation. The recent studies in this
field afford very definite practical applications of scientific methods.
Distribution.
The orchids are distributed over all parts of the world with the exception of the polar regions and the great deserts. About 85 per cent of the species occur in the tropical and subtropical regions. Here they are found to a great extent in the mountainous districts. In some parts of the Himalayan region, the orchids constitute the most abundantly represented family of plants in point of number of species. Most of the tropical species are endemic. The widely distributed species are found in the North Temperate and the Subarctic zones. They include such forms as Calypso bulbosa (formerly known as C. borealis), Microstylis monophyllos, Liparis Loeselii, and species of Orchis (or Galeorchis). These are found throughout the northern regions of both hemispheres. The greater number of the orchids are distributed in three regions of the earth: (1) The tropical African region, including the islands to the east, furnishes comparatively few species to cultivation.
These mostly belong to the genera Angraecum, Bulbophyllum, and Disa. This region also contains a number of endemic genera not of great interest to cultivators, and representatives of such widely distributed genera as Habenaria, Liparis. Microstylis, Epipactis, and others. (2) Unusually rich in genera is the region of tropical Asia, including the neighboring groups of islands. Typical of this region are the large genera Dendrobium, Eria, and Bulbophyllum, and many smaller genera, including Paphiopedilum, Coelogyne, Cymbidium, Sarcanthus, Saccolabium, and Vanda. Among the genera common to this region and the African region are Bulbophyllum, Phaius, Calanthe, Liparis, and Microstylis. (3) The tropical American region, embracing Mexico, Central America, tropical South America, and the neighboring islands, occupies an isolated position and consequently contains an unusually large number of endemic genera, many of which are represented by hundreds of species. Besides the large endemic genera Epidendrum, Pleurothallis, Oncidium, and Odontoglossum, this region contains many of the commonly cultivated genera, among which may be mentioned Cattleya, Laelia, Masdevallia, Schomburgkia, Brassavola, Lycaste, Peristeria, Stanhopea, Gongora, Zygopetalum, Miltonia, Phragmipedilum, and many others. Some genera, among them Vanilla, Bulbophyllum, Calanthe, Liparis, and Microstylis, are common to both this region and the Old World. Compared with these great floristic regions, the temperate lands of the southern hemisphere are of less importance. Of the south African genera, Disa and Calanthe furnish a few species valuable to cultivation. Australia contains many genera in common with the tropical Asiatic region, but few of the cultivated species are derived from there. In temperate South America the orchids are sparsely represented by a few species of Epidendrum,Oncidium, Spiranthes, Habenaria, and a few other genera. From a horticultural standpoint, the species of this region are of little importance. About twenty genera are found in the northeastern United States and Canada, mostly in swamps and moist grounds; among them are the Cypripediums or lady's slippers, and many beautiful plants in the genera Habenaria, Pogonia, Calopo- gon, Arethusa, and Calypso.
Habitat.
With regard to their habitat, the orchids are either terrestrial or epiphytic. The terrestrial orchids include the species of the temperate regions and many of the largest and most stately orchids of the tropics. Many of these are ornamental, even when not in flower. A few are attractive on account of their variegated foliage and some, like Sobralia and Selenipedilum, are admired on account of their tall graceful stems.
Most of the terrestrial orchids are green plants which obtain their carbon supply from the carbon dioxide of the air, but a few forms either lack chlorophyl entirely or possess it only in traces too small for normal photosynthesis. These forms are saprophytic in their mode of life and depend for their carbon food upon the organic matter of the humus. The appellation of parasites, which is sometimes given to these forms, is erroneous. True parasites are not known among the orchids.
In the saprophytic orchids, the subterranean part is either a much-knotted coral-like rhizome devoid of true roots (Corallorhiza, Epipogon), or a subterranean rootstock producing numerous crowded fleshy roots (Neottia, Galeola). The annual shoots are yellowish, brownish, or reddish, without true leaves, but bearing scales and a terminal inflorescence which may be reduced to a solitary flower. Very curious are the members of the Javan genus Galeola, whose leafless climbing stems attain a height of 100 feet, ascending trees by means of roots that arise opposite the scale- leaves, and producing a terminal and many lateral racemes in the upper part of the stem. The saprophytic orchids are not cultivated except occasionally in botanic gardens, as the conditions necessary for their existence are not readily imitated.
The epiphytic orchids exhibit the most varied forms. They are confined to the tropics and subtropies, where they inhabit branches of trees, dead trunks, and often barren rocks in exposed places. They grow mostly in regions where a part of the year is unfavorable to vegetation. As an adaptation to these conditions, they have developed special food reservoirs (pseudobulbs) terminating each season's growth. In this group there are comparatively few plants of attractive habit. They are usually devoid of graceful foliage, each pseudobulb bearing a few stiff leathery leaves. The older pseudobulbs become shriveled and leafless, detracting from the appearance of the plants, and in Pleione the plants are entirely leafless at the flowering time. In some of these, however, the pseudobulbs are numerous and closely crowded, and retain their foliage, making plants of neat compact habit (Coelogyne, Miltonia). In their mode of life, the epiphytic orchids resemble the green terrestrial orchids. For their mineral nutrients they are dependent upon the material which is mostly the residue of decayed organic matter which accumulates among their roots. They arc not saprophytic or parasitic.
Morphology of the vegetative parts.
All orchids are perennial herbs which, according to their mode of growth, fall into two groups—the monopodial and the sympodial.
In the monopodial orchids, the growth of the main stem is continued indefinitely by the terminal bud. (Figs. 2624-2627.) Lateral branches are frequently produced, but they do not regularly assume the part of the main axis and do not under ordinary conditions exceed it in length. The growth of the main stem and its branches may be interrupted for a time by a period of rest, but such interruption is not manifested on the stem by the formation of scales and juvenile leaves when growth is resumed. All leaves are similar. The habit of the monopodial orchids is various. In spite of their indeterminate growth, they do not usually attain great size. This fact is explained by the slow growth of the plants, which often require several months to develop a single leaf.
Nevertheless, some of the species attain stately proportions. The climbing species of Renanthera sometimes reach a length of 12 feet or more in greenhouses. Some of the vandas, aerides, and angraecums form handsome plants 1 to 2 feet high and well clothed with long distichous leaves. (Figs. 2626, 2627.) While these forms grow into tall leafy plants, others, like Phalaenopsis, remain almost stemless and possess only a few large fleshy leaves. The extreme reduction is represented by such forms as Polyrrhiza funalis, in which the stem is reduced to a mere scaly bud seated on a mass of tangled green roots which perform the function of photosynthesis.
In the sympodial orchids, the growth of each shoot is definitely terminated usually after one, rarely after two or more seasons. The development of the plant is continued by buds originating in the axils of the scale- leaves at the base of the parent shoot. (Figs. 2628, 2629.) The lower part of each new axis is prostrate at first and often subterranean and bears only scales. It is known as the rhizome. In many terrestrial orchids of the temperate regions, the lower terminal part of the rhizome forms a tuberous root from whose apex the shoot of the next season arises. (Fig. 2630.) In a few sympodial orchids with perennial stems and climbing habits, branches originate in the axils of the stem- leaves (Vanilla). These bear a strong resemblance to the monopodial orchids, but all the branches as well as the main stem are finally terminated by inflorescences.
The general habit and appearance of orchid plants depends to a great extent on the nature of the rhizome. When this is long, the plants have a loose straggling habit (Epidendrum). When it is short, the plants are compact (Masdevallia, Cattleya, Coelogyne). The rhizome may be much branched and give rise to numerous upright shoots (Sobralia, Coelogyne, Disa), or it may be simple and give rise to only one shoot annually as in many of our native orchids. In some species, the rhizome assumes suberect or climbing habits (Lycaste).
The upright part of the axis presents a great diversity of forms which may be grouped in two classes according to the position of the inflorescence. This may be either terminal or lateral.
In the forms with a terminal inflorescence, the leafy part of the stem may be very short so that the leaves appear as a rosette on the ground while the upper part of the stem bears bracts from whose axils the flowers appear (Goodyera, Orchis rotundifolia, Cypripedium acaule) but generally it is more developed and bears a succession of leaves which are gradually reduced to bracts in the upper part (Habenaria, Cypripedium. Disa, Thunia). In Selenipedilum and Sobralia, the tall reed-like stems reach a height of 6 to 15 feet and often form dense thickets. In Vanilla the stems are long, branched, and climbing. In many of the epiphytic forms the stem is thickened into a pseudobulb. This may consist of a single internode which bears one or two leaves at its summit (Coelogyne), but more frequently several internodes are enlarged to form the pseudobulb, which is then clothed with leaves at least when young, and later bears the scars of fallen leaves (Laelia, Cattleya, Epidendrum). Figs. 2631 and 2632 show the two forms of pseudobulb. Sometimes the whole stem is more or less fleshy without being enlarged into a distinct pseudobulb (Epidendrum spp.).
An equally varied display is presented by the sympodial orchids having a lateral inflorescence.
Nearly stemless forms, or forms in which the stem is developed as a subterranean structure often of curious configuration, occur in the Phaiinae (Phaius, Calanthe, Bletia), the Cyrtopodiinae (Lissochilus, Warrea), and the Corallorhizinae (Corallorhiza, Aplectrum). In others, the stem is developed as a pseudobulb consisting of several internodes clothed with leaves (Cymbidium, Mormodes, Catasetum, Chysis), or it is elongated and cane-like as in Dendrobium, which, however, may belong to the terminal-flowered forms since some of the near relatives of this genus produce terminal flowers. In species of Grammatophyllum and Cyrtopodium, the tall leafy pseudobulbous stems attain magnificent proportions, reaching a height of 3 to 15 feet. (Fig. 2633.) In the greater number of the lateral- flowered forms, only a single internode of the stem is enlarged to form a pseudobulb. (Fig. 2634.) Such is the case in Odontoglossum, Oncidium, Bulbophyllum, Trichopilia, Zygopetalum, Lycaste, Stanhopea.
The inflorescence of the orchids is throughout of the indeterminate type, that is, truly terminal flowers are not produced. Even in those cases in which the flower is solitary, the presence of a few bracts above it show its axillary position. In the monopodial orchids, the inflorescence is of necessity always axillary since the growth of the vegetative shoot is indeterminate, but in the sympodial orchids it may be either axillary or terminal, as described above. In Caelogyne cristala, and a few others, the inflorescence is terminal on special branches of the sympodium.
The form of the inflorescence is various. Solitary flowers occur in many genera, as Cypripedium, Lycaste, Anguloa, and others, but more commonly the inflorescence is racemose or paniculate. The raceme may be close and compact as in some of the monopodial orchids (Aerides, Saccolabium), or loose with few to many flowers, as in most of our native orchids as well as in most of the commonly cultivated species. In Renanthera, the gigantic racemes attain a length of many feet. Large paniculate inflorescences are characteristic of some species of Oncidium and related genera. The inflorescences are sometimes of a climbing habit and attain a height of several yards. The large perennial panicles of some species of Phalaenopsis bear as, leaves so that the whole upper part of the plant may be considered as a huge panicle.
Morphology of the floral parts.
No group of plants exhibits so great variety of modifications of the floral structures as the orchid family. Some of the forms are shown in Figs. 2635, 2636, 2637. Fundamentally the flower is of the liliaceous type; but, by the supression of some parts and the modification of others, the structure of the flower has been so changed that in its outward appearance it bears little resemblance to the typical monocotyledonous flower. In flowers of the liliaceous type, there are normally present two outer whorls of floral organs, the sepals and the petals, two whorls of stamens, and an inner whorl representing three carpels. In the orchid flower, the two outer whorls, the sepals, and petals are developed. Of the stamens, only two are fertile in the Diandrae (Cypripedium and related genera), while in all the other orchids (Monandrae) only a single stamen is fertile. The three carpels are always present. The three corresponding stigmas are developed in the Diandrae, while in most of the remaining orchids only two stigmas are receptive (Monandrae). (See Fig. 2638.)
The relation of the parts of the flower to one another is greatly changed by the growth of the floral axis. This is convex in the very young stages of development but it soon becomes cuplike by the cessation of growth of the center and the more rapid growth of the peripheral zone. A hollow or tubular axis is thus produced, within which are formed three longitudinal ridges or placenta: upon which the ovules are borne. The hollow floral axis constitutes the "inferior ovary" of the orchids (Fig. 2639) and at the same time acts as the stalk or pedicel of the individual flowers of the inflorescence. The ovary is structurally 3-celled. (Fig. 2640.) Besides the carpellary cavity, the axis of many orchids contains another cavity which lies toward the labellum or lip and opens at the base of it. This is a nectary. It may be considered in the nature of the cavity of an adnate spur of the labellum. In the embryonic state, the orchid flower is so oriented that the labellum is situated on the side of the flower toward the axis of the inflorescence, as shown in Fig. 2638; that is, it points toward the apex of the inflorescence. In a few forms this condition is permanent, but in the greater number of orchids the ovary or axis is variously bent or twisted so that in the mature flower the labellum is on the side of the flower away from the floral axis or, generally speaking, on the lower side of the flower.
Of all the floral organs the sepals are the least modified. These comprise the outside whorl in Fig. 2638. The one originally opposite the axis of the inflorescence, but which by reason of the turning of the flower just described usually occupies a position adjacent to the axis or on the upper side of the flower, is known as the odd sepal. By reason of its actual position with reference to the flower, it is sometimes called the upper sepal. The other two, which were originally adjacent to the axis of the inflorescence, are the paired or lateral sepals. In most orchids, the lateral sepals are asymmetrical, but noteworthy modifications occur only in a few genera. Sometimes the lateral sepals are partly or entirely united (Cypripedium, Oncidium). In Masdevallia, all the sepals are united into a short tube at the base, and expand above into three blades terminating in long tails. Occasionally, the odd sepal is spurred or saccate (Disa) and very commonly differences in size exist between it and the lateral sepals.
Of the members of the second whorl, the two lateral ones are usually petal-like while the one opposite the odd sepal is specially modified, and is known as the labellum (l, in Fig. 2638). In most genera the lateral petals resemble the odd sepal, although minor differences in form, size, and color are of frequent occurrence. This resemblance is most striking when these parts have some unusual form, as in Oncidium papilio, in which they resemble the antennae of an insect, or in Phragmopedilum caudatum, in which they are long caudate, attaining a length of 3 feet. In some genera, the lateral petals show no resemblance to the odd sepal (Huttonaea. Masdevallia, Achrochaene). Asymmetry of the lateral petals occurs very frequently.
The odd petal, or the labellum, presents the greatest diversity of form of all the floral organs. Sometimes it is small and inconspicuous (Disa), or it is like the lateral petals (Goodyera). As a rule, however, it is much larger than the lateral petals (as in Fig. 2637), and often it is the most conspicuous part of the flower (Oncidium, Cypripedium, Odontoglossum Londesboroughianum). In a few genera the labellum is bifid (Vanda, Listera), but in the greater number of orchids it is evidently three- lobed. One of the most common forms which the labellum assumes is that of a trumpet-shaped tube whose sides are formed by the lateral lobes, while the middle lobe is expanded into a variously shaped blade which is often of a deeper shade than the rest of the flower and ornamented by crests and ridges and color-markings of various kinds which are thought to be of service to the flower by attracting insects and guiding them to the nectar and hence to the pollen and stigmas. This form of labellum is characteristic of many of the most beautiful orchids in cultivation (Cattleya, Laelia, Dendrobium, Phaius). Frequently the labellum is more or less concave, and in Cypripedium and related genera it has the form of a sac (Fig. 2636) often compared to a shoe as the name "lady's slipper" indicates. In many species, the labellum is strangely transformed and more or less distinctly segmented into a basal part, the "hypochil," and a terminal petaloid portion which is then designated as the "epichil." Sometimes the differentiation is carried still further and an obscurely defined section, the "mesochil," is recognized between these two. The hypochil is the stalklike, or somewhat concave winged part which joins the column. It is not clearly distinguishable from the foot of the column described below. The mesochil is usually provided with two lateral cirrhous appendages termed "pleuridia," and a central callus known as the " mesidium " (Phalaenopsis, Stanhopea, Peristeria, Gongora). (Fig. 2641.) The epichil is the simple or lobed terminal part of the labellum. In color and consistency it usually resembles the lateral petals. Often it is movably attached to the mesochil. In some forms of the Pterostylidinae the labellum is sensitive, and when irritated by an alighting insect closes sharply against the column, entrapping the animal.
The morphological center of the flower is occupied by a fleshy elongation of the floral axis known as the column. This is short and inconspicuous in some forms, but in most species it is well developed. It is usually bilaterally symmetrical. The posterior surface is convex while the anterior surface, toward the labellum, is concave. Usually the column is curved toward this face.
In a few forms, like Cycnoches, the curvature is very marked, while in Coryanthes the column is asymmetrically bent. Within the column is a canal continuous with the carpellary cavity. (Fig. 2642.) The column is primarily of importance because at its upper end it bears the stamens and the stigmas and auxiliary structures which function in the pollination of the flowers. Besides these organs, it sometimes bears a number of outgrowths and appendages which give it a very complex appearance. Often the labellum does not appear to be attached directly to the column, but is borne upon a special fleshy outgrowth at its base known as the "foot" of the column. Between the forms in which the foot of the column is not developed and those in which it is present, no distinct line can be drawn. In our native orchids it is mostly absent. In Gram- matophyllum there is a small cuplike depression upon whose anterior wall the blade of the labellum is attached with a narrow base. It is here a matter of interpretation whether the anterior wall of the cup is regarded as a part of the labellum or as the foot of the column. (Fig. 2643.) In other cases where the foot is more distinctly developed, the labellum is often plainly attached to its lower side, as in Paphinia, Pescatoria, Phaius, Bulbophyllum. (Fig. 2644.) Frequently the lateral sepals are decurrent upon the foot or entirely attached to it (Bulbophyllum Achrochaene, Fig. 2(545). In some forms the lateral sepals and the labellum are borne near the end of the foot while the lateral petals are decurrent upon it (Batemannia). Sometimes the lateral sepals and the labellum are carried entirely away from the other parts by the elongation of the foot of the column, thus giving the flowers strange and fantastic forms (Drymoda, Gongora, Aerides). When the lateral sepals or the petals are decurrent upon the foot they, together with the labellum attached at the apex, often form a "chin" or "mentum" which is present in many orchids, such as Dendrobium, Pescatoria, Lycaste, Batemannia. (Fig. 2646.) Frequently the base of the mentum is extended below into a sac or spur of various forms and length. More often the spur arises from the labellum itself (Phaius, Platanthera). Within the cavity of these spurs or sacs, honey is secreted, and often the walls themselves contain juices which are sought by insects.
The upper part of the column bears the stigmas and the stamens. In the Diandrae, the three pistils are fertile, as indicated by the more or less evidently three-lobed stigma (Figs. 2647 and 2648), but in the Monandrse only two stigmas are receptive. The place of the third is occupied by the curious "rostellum," which separates the anther-bed from the stigmas and prevents the pollen from falling directly upon them (Fig. 2642). The stigmas are usually flat surfaces sunk in a depression in the column below the rostellum. In a few genera they are elevated on stalks (Habenaria), and in Sophronitis they extend partly along two wing-like projections of the column. The essential organs, in other forms, are shown in Figs. 2647-2652.
The stamens in the Diandrae are situated laterally on the column under a shield-like staminodium which is developed in place of the odd stamen of the outer whorl. In the Monandrae, the stamen is situated at the dorsal margin of the column. Its position is sometimes erect, but more frequently it is bent downward with the anther either pendent (Coelogyne, Fig. 2650), or lying in a depression, the "clinandrum" or "anther-bed," in the top of the column. From the dorsal part of the column a petaloid appendage often arises and extends above the anther. The sides of the anther-bed are formed by outgrowths of the column. They are often developed as crests, ears, or winglike structures ornamenting the column and enfolding the anther. The floor of the anther-bed is formed by the rostellum.
The anther sometimes remains two-celled, but more frequently the cells are further divided, by longitudinal partitions or cross-walls, into four or eight cells. In a few cases, six cells are formed, probably by the abortion of some of the cells.
The pollen is powdery in some cases, but usually the grains are united by means of a viscid substance into waxy masses termed "pollinia." The number of pollinia corresponds to the number of anther-cells. In many genera, the viscid substance uniting the pollen-grains is prolonged beyond the pollen-mass and hardens into a stalk or "caudicle" within the anther- cell (Fig. 2651). One or two pollen-masses are attached to each caudicle. When the anther dehisces, the caudicles come into contact with masses of sticky matter formed by the disorganization of cells on the upper surface of the rostellum. In many orchids, this substance itself forms the adhesive disk by means of which the pollinia become attached to insects. In others a strip of tissue is separated from the rostellum by the disorganization of the underlying cells, and forms a stalk which in this case is known as the "stipe." When a stipe is formed by the rostellum, the caudicle of the pollen-masses is not produced. In that case, the pollinia become directly attached to the stipe when the anther dehisces. The other end of the stipe forms the adhesive disk. (Fig. 2652.) Whatever its origin, the stalk with its adhesive disk is one of the most important parts of the mechanism by which the transport of the pollen-masses from flower to flower is brought about and by means of which cross- pollination is insured. The details of the process by which this is accomplished have been beautifully explained by Darwin in his classical work, "The Various Contrivances by Which Orchids are Fertilized by Insects."
Dimorphic and trimorphic flowers occur in a few orchids. In the inflorescences of a small group of Oncidiums (Heterantha), only few normal flowers are produced together with many smaller sterile ones which lack the column. In Renanthera Lowii the upper flowers of the long inflorescence differ in form and color from the others. The most unusual condition exists in Catasetum, in which there are three very different types of flowers. In some years the same plant produces only one type and in other years all types on a single inflorescence.
The flowers of orchids are commonly noted for their longevity. When not pollinated, the flowers of most genera remain fresh for thirty to forty days, and in some genera even for much longer periods. Only a small n u m b e r of genera have flowers that wither in a few days (Sobralia, Cirrhopetalum). The persistence of the flowers greatly increases the chances for pollination, which, since it is dependent on particular agencies, is more or less uncertain. After pollination has been effected, the flowers soon wither.
The fruit of orchids is usually a dry capsule, requiring a long time to ripen, so that if an orchid flower is fertilized in one rainy season its seeds are not disseminated until the next wet period. Very few have fleshy fruits which dehisce imperfectly or not at all. In them the seeds are liberated only by the decay of the pericarp (Vanilla). The seeds of orchids are minute and extremely numerous, the number in a single capsule having been estimated for different species from several thousands to over a million. The seeds consist of a dry loose large-celled testa inclosing a rudimentary embryo, which in most genera is entirely un- differentiated. (Fig. 2653.)
Symbiosis.
So far as known, the roots of all orchids, with the exception of occasional individuals, are inhabited by fungi which live within the tissues either symbiotically or at least without causing any apparent injury to the plant. The fungus hyphae are primarily found in the cortical tissues, but usually two or three of the outer layers of cells of the cortex are not infected. In the epidermis the fungus is found only in the cells bearing root-hairs, through which long hyphae pass out into the substratum. The central cylinder and the growing apex of the root are not infected. The extent to which the fungus passes upward in the plant varies with different species and with the condition of the roots. In Neottia, Goodyera, and Corallorhiza the lower part of the stem is invaded sometimes up to the first node. In Epipactis, Cypri- pedium, and Listera, the roots and rhizomes contain much woody tissue. In such forms, many of the roots are free from fungi, and in the remaining roots, as well as in the rhizomes, the distribution of the fungus is irregular. The basal parts of the roots, which are more or less woody, are not infected; and occasionally individual plants are found which appear to be free from the fungus. In the roots of epiphytic orchids, also, the distribution of the fungi is irregular, only scattered islands of cortical tissue being as a rule infected. Only the parts of the roots which are in contact with the substratum contain fungi. In forms like Vanda and Vanilla, with superficial roots, only the side of the root adjacent to the substratum is infected, while the other chlorophyl-bearing side is free.
Within the cells, the fungus has the form of closely coiled and interwoven masses of hyphae, except in the root-hairs and in the velamen,—the spongy outside covering of the roots of epiphytic orchids,—where long hyphae occur. The endophytic mycelium is, as a rule, connected with external mycelium in the substratum by means of hyphae passing through the root-hairs, or, where these are absent, as in Neottia Nidus-avis, through the epidermal cells of the rhizome and the roots. In some forms, like Neottia and the epiphytic orchids, such communications have been only sparingly observed, while Corallorhiza and most of the terrestrial orchids have abundant connections with the mycelium in the substratum.
The plants are sometimes permanently infected through the seedling in the way described farther on. Infection also takes place through the root-hairs. When the rhizome and the upper part of the roots are free from fungi, infection must of necessity take place in this way. In epiphytic orchids, and probably in terrestrial orchids also, repeated infections thus occur. t In some terrestrial orchids, in which the fungus invades the rhizome, the hyphae grow out directly from this into the new roots, and also into the bud for the following year. In such forms only a single infection is necessary to establish a permanent symbiosis.
It is generally held that the mycorrhiza fungi supply their hosts with nutrients. That the non-green forms like corallorhiza are supplied with organic carbon compounds in this way can scarcely be doubted, for these plants, lacking chlorophyl, cannot elaborate their own carbohydrates from the carbon dioxide of the air. It is certain, also, as will be described later, that the germination of orchid seeds and the early stages of development of the seedling do not take place without the intervention of the mycorrhiza fungi, but the function of the fungi in these processes remains still to be investigated. To what extent the mycorrhiza fungi function in supplying the plants with water, salts, and organic nitrogenous compounds, is not known. For the greater number of orchids that are equipped with chlorophyl and which can, therefore, utilise the carbon dioxide of the air for the production of carbohydrates, it is not likely that the root-fungi are necessary for supplying them with carbon compounds. There is some evidence, however, that the fungi have a part in supplying the plants with nitrogenous compounds and possibly with phosphorus and potassium also. The fact that the hyphae coils are finally digested in the cells and that the substances which they contain thus become available to the plant, throws no light on this problem for the substances in the hyphae may have been derived from the plant itself. Investigations up to the present time have shown that orchids do not assimilate free nitrogen from air by the aid of their endophytic symbionts, nor do the fungi themselves in pure cultures fix free atmospheric nitrogen.
Seedlings.
The growing of orchid seedlings has always been surrounded with much mystery and secrecy. In the large orchid establishments, the secret methods which the expert growers were supposed to possess were carefully protected by locked doors and painted glass, and visitors were seldom admitted to the houses. Yet it was evident that in spite of the carefully guarded practices, chance seemed to play an important part in the culture of orchid seedlings. Rarely were the expert growers uniformly successful. Of the vast number of genera imported, only cattleyas, odontoglossums, cypripediums and a few others could be grown with even a fair assurance of regular success. Some growers were unusually successful with one group and some with another, but generally all were not equally successful with all kinds. The key to this situation was furnished by Noel Bernard who, in 1903, attempted to grow seedlings of a hybrid between Cattleya Mossiae and Laelia, purgurata under aseptic conditions and found that the embryos swelled and formed green spherules, but that they failed to develop further even after weeks, and finally died. If, however, the seeds were sown on pure cultures of the endophytic fungus isolated from the roots of these plants, the embryo developed normally, forming a spheriod body which soon produced a cotyledon and papillae with long root-hairs. Further investigations, chiefly by Bernard and by Burgeff, showed that the germination of orchid seeds does not occur except in the presence of the root fungi. Even seedlings of such little mycotrophic forms as Cypripedium and Epipactis, will not develop unless infected, although the mature plants of these species are often found without fungi and do not require their presence.
The infection of the orchid embryo takes place through the suspensor by means of which the embryo was attached to the nutrient tissue of the ovule (Fig. 2654). From the suspensor the fungus invades the cells in the lower region of the embryo, except the epidermis. The cells become filled with dense interwoven gnarles of hyphae like those in the roots. The coils in the inner cells undergo a process of digestion, but those in the outer cells remain intact and send hypha3 through the root-hairs of the papillae into the soil. New papilla with long absorbing hairs are soon developed and the cotyledon and leaves begin to be differentiated. After three to four months, roots are produced and the young embryo begins to assume the characteristic form of an orchid seedling (Fig. 2655).
From these facts it is apparent that for the growing of orchid seedlings it is absolutely essential that an association of the seed with the proper root-fungus be brought about. In practice, this has often been accomplished by the sowing of the seeds on pots containing the parent plants. This method, however, has many disadvantages. The plants cannot be repotted while the seedlings are growing, and the seeds are likely to be washed away in watering, since they cannot be readily protected by a proper covering. Better success can be secured by the use of straight walled glass jars with loose glass covers. These are filled with finely chopped sphagnum, which is well pressed into the jar. The whole is then sterilized in a steam-box for one hour on three successive days in order to kill bacteria and spores of molds which are likely to overrun the seedlings. After sterilization, the jars should be allowed to stand for a few days. Those in which -molds develop should be discarded. The sterile jars may then be inoculated with the root-fungus from the species of orchid to which the seed-plant belongs. For this purpose, portions of infected roots should be cut into small pieces with a sterile knife and scattered over the sphagnum seed-bed. Great care should be observed at all times to avoid the introduction of foreign spores from the air. It should also be borne in mind that only the covered roots contain the fungus, and that generally only the soft tissues from ½ to 1 inch back from the root-tip are most abundantly infected. As soon as the root-fungus has grown through the sphagnum, the seeds should be sown in the jars. In the collection, and handling of the seeds, all possible precaution should be taken to prevent contamination.
While the difficulties involved in these manipulations are considerable, they are not insurmountable, and it is not unlikely that in time means will be found to remove many of the uncertainties which at present attach to the growing of orchid seedlings. With the increasing demand for orchids for cut-flowers and for general florists' use, and the depletion of the sources of supply of imported orchids,—especially of the rarer endemic varieties,—the growing of seedlings will become more and more a matter of necessity. The production of new and improved varieties, and the preservation and multiplication of rare sorts will be greatly facilitated when the growing of seedlings is freed from its many uncertainties. The seed-grown plants have many advantages over the imported ones. They are from the start better adapted to greenhouse conditions. They are hardier and more resistant and can be grown into plants of better form. They also flower more freely and often can be made to bloom twice a year.
Hybrids.
One of the most fascinating phases of orchid-culture is the production of hybrids. By the crossing of different genera and species, numerous new orchids have been produced, many of which are superior to the native species. The first orchid hybrid to be produced in cultivation was Calanthe Dominii, a cross between C. masuca and C. furcata. It was raised by Mr. Dominy in the nursery of James Veitch & Son, and flowered in 1856. Other hybrids, including the beautiful Calanthe Veitchii, appeared in the following years, and in 1861 the same grower produced the first bigeneric hybrid, Goodyera Dominii, which was a cross between Haemaria (Goodyera) discolor and Dossinia marmorata. Since that time the interest in orchid hybridization has grown greatly. The number of orchid hybrids now is between 3,000 and 4,000. Rolfe and Hurst record twenty-three genera which have entered into bigeneric hybrids, and many cases in which three genera have entered into the hybrid. In some hybrid genera, like Laeliocattleya, the forms far outnumber the species of the parent genera.
The pollination of orchid flowers requires a little skill and patience and a knowledge of the parts of the flowers described earlier in this article, but otherwise offers no great difficulties. Only strong and vigorous plants should be chosen for seed-bearing, since the process greatly exhausts the plant and sometimes even causes its death. The pollinia are mature and the stigmas are receptive when the flower is fully open. When it is the purpose to produce hybrids, it is well to remove the pollinia of the plant that is to bear the seed since the possibility of accidental interference by the plant's own pollen is thus prevented. Even when it is intended merely to grow non-hybrid seed, this course is to be recommended, since, in nature, the orchids are habitually cross-pollinated. The pollination is easily accomplished. To this end, the pollen-masses are removed from the anther by means of a sharp lead- pencil or a pointed stick and placed on the stigmatic surface. In the Cypripediums and related genera, the pollen- masses are exposed, but in most of the other orchids the pollen is covered by the anther, which can be readily removed. The pollinia can be picked up by touching the adhesive disk with the stick or lead-pencil. Usually several pollen-masses will be thus withdrawn, but as a rule it is best to place only a single one upon each stigma. Fewer seeds are thus ripened but these are better nourished and produce more vigorous seedlings than seeds from full capsules. The methods of sowing the seed are the same as already described.
The nomenclature that has been most frequently adopted (aside from treating them as direct species names) for simple orchid hybrids between two species of the same genus consists in the application to the hybrid of a Latin name of specific rank but preceded by a x. Thus Calanthe x Veitchii signifies that the plant so named is a hybrid between two species of Calanthe. Sometimes non-latinized names are used, as Cattleya x "Nymph." In the case of bigeneric or trigeneric hybrids, the name of the hybrid is usually formed by the combination of parts of the names of the parents or of the whole name of one parent and part of that of the other, as Epiphronitis (Epidendrum and Sophronitis), Laeliocattleya (Laelia and Cattleya), Brassocattlaelia (Brassavola, Cattleya, and Laelia).These are written as one word without hyphens or capitals at the beginning of the second or third parts. For further details concerning orchid hybrids and lists of all known forms, see G. Hansen, "The Orchid Hybrids," London, 1895; E. Bohnhof, "Dictionnaire des Orchidees Hybrides," Paris, 1895; R. A. Rolfe and C. C. Hurst. "The Orchid Stud-book," Kew, 1909, and Sander & Sons, "Orchid Hybrids," St. Al- bans, 1912 (?). For other suggestions on the nomenclature of orchid hybrids, see the entries Adamara, Linneara, Lowiara.
Foliage plants.
The Physureae, a small group of orchids distributed in tropical Asia and the Malay Islands, with a few species in Africa and North America, are remarkable for their beautifully variegated leaves (Physurus, Anoectochilus). The plants themselves are usually small, with the habit of Goodyera, a North American representative of the group. Variegated or mottled leaves occur also in some other groups (Cypripedium, Goodyera, Phalaenopsis, and Oncidium).
Historical sketch.
While the native orchids of Europe excited the interest of the herbalists of the sixteenth century, the epiphytic forms of the tropics did not become known to botanists until a much later period. By the end of the seventeenth century, a few species had been described and figured by Rheede tot Draakenstein, Sloane, Plumier, and others. In the second edition of Linnaeus' "Species Plantarum" (1763), thirty species of epiphytic orchids are described under Epidendrum, which, at that time, was made to include all epiphytic orchids from the tropics. In 1805, Willdenow, in his edition of the "Species Plantarum," listed 391 orchids, including 140 epiphytic species. In the nineteenth century, through the exertions of many collectors, the number of known tropical orchids rose rapidly. For the descriptions of the numerous forms coming in during that time we are chiefly indebted to efforts of Lindley and of Reichen- bach.
Attempts at the cultivation of tropical orchids apparently did not begin until early in the eighteenth century. The first edition of Miller's "Gardener's Dictionary," in 1731, describes twenty native European species under Orchis, but no tropical form is mentioned. About this time, however, plants began to be introduced into English conservatories by missionaries and officers who visited the tropics. In 1731, Bletia verecunda was received from the West Indies. The vanilla was cultivated by Miller in 1759, and was at that time fairly well known in English conservatories. In 1789, Commodore Gardner sent plants of Epidendrum fragrant from the woods of Jamaica. One of these flowered two years later and was the first orchid figured in Curtis' "Botanical Magazine" plate 152 (as E. cochleatum). In Martyn's edition (1807) of Miller's "Gardener's Dictionary," 124 orchids, including the vanilla, were listed under Epidendrum.
The middle part of the nineteenth century is remarkable for the great number of new and rare forms introduced, and for the large sums often paid for striking novelties. As early as 1855, a plant of Aerides Schroederi brought something over $430 (G.C. 1855, page 775). In 1875, a plant of Dendrobium Wardianum was sold at Stevens' auction rooms for over $500 (G.C.1875, I, page 502), and in the same year at the sale of the collection of John Russell at May field a plant of Saccolabium guttatum sold for $313, one of Saccolabium Russellianum for $141, and an Oncidium splendidum for about $160 (G.C. 1875, II, page 467). In 1879, a fine plant of Vanda caerulea sold among other orchids of a large collection for about $460 (G.C. 1879, I, page 27). These are only instances with which the records of that period are replete. Although such prices were realized only for exceptional plants, there was always a large demand for good plants of all types, for which considerable sums were paid. The prospects of great reward caused collectors to scour every part of the tropics, risking their lives in the mountains, jungles, and fever-haunted swamps. Vast numbers of plants were imported and many died on the voyages, or subsequently, for want of rational treatment; but the large importations served to popularize the plants and to increase the demand for them. In time the climatic conditions under which they grew in their native regions became better known, and the plants were treated more in accordance with their requirements. Fewer orchids are imported at the present time, for the rewards are not so great as formerly, and other means for multiplying the stock are supplanting importation to a great extent. Yet the interest in orchids is not abating, but is steadily becoming more widespread. Although the large collections of fanciers are not so distinctive of orchid-culture as formerly in this country, the use of the plants is becoming far more general. The flowers have become a regular part of the florist's stock and thousands are annually sold in the markets. The ease with which they are grown, their great range of fine colors, and the wonderful keeping qualities of the flowers insures them an ever-increasing popularity.
Literature.
A large and special literature on orchids has grown up. Many magnificent folios and smaller works have been devoted to the illustration and description of these plants. Notable among these are "Sertum Orchidaceum," by J. Lindley, London, 1838, a large folio containing forty-nine colored plates of East Indian orchids; "The Orchidaceae of Mexico and Guatemala," by J. Bateman, London, 1837-1843, an even more sumptuous work, with forty plates, of which only 125 copies were published; "A Monograph of Odontoglossum," London, 1864-1870, by the same author; "Pescatorea," Brussels, 1860, by J. J. Linden; "Reichenbachia," St. Albans and New York, 1888-1890, second series 1892-1894, by F. Sander, folio, two volumes, with ninety-six colored plates; "A Century of Orchidaceous Plants," London, 1849, by W. J. Hooker, a quarto volume containing 100 plates selected from Curtis' "Botanical Magazine," "A Second Century of Orchidaceous Plants," London, 1867, by J. Bateman, contains 100 plates of reproductions from the same work; "Xenia Orchidacea," Leipzig 1858-1900, by H. G. Reichenbach, three quarto volumes containing 300 partly colored plates; "The Orchid Album," London, 1882-1897, by Robert Warner and B. S. Williams, eleven quarto volumes, containing 528 plates; "Illustrations of Orchidaceous Plants," London, 1857, by T. Moore, contains 100 plates selected from the "Botanical Register" and Sweet's "British Flower Garden;" "Dictionnaire Iconographique des Orchidees," Brussels, 1897-1907, by A. Cogniaux and A. Goosens, eight volumes of colored plates of flowers; and "Orchids, the Royal Family of Plants," Boston, 1885, by Harriet S. Miner, contains twenty-four plates with a popular account. Two periodicals, "L. Orchidophile, Paris, 1881-1892, and "Lindenia," Ghent, 1885-1906, were almost wholly devoted to the illustration of orchids, while "The Orchid Review," London, 1893, and continuing, is a more popular journal devoted to the interests of orchid-culture in general. Many plates and descriptions of orchids have appeared in other serials like Curtis' "Botanical Magazine" and Lindley's "Botanical Register." Many of Reichenbach's species were described in the "Gardeners' Chronicle." A great many large manuals and handbooks have been published. Among them may be mentioned "A Manual of Orchidaceous Plants Cultivated under Glass in Great Britain," by James Veitch & Sons (A. H. Kent), London, 1887-1894, a very comprehensive manual of two volumes, containing many engravings; "Orchids: Their Culture and Management," by W. Watson, London. 1890, new edition, New York, 1903, with twenty colored plates and numerous engravings; "Les Orchidees Exotiques et Leur Culture en Europe," by L. Linden, A. Cogniaux and G. Grignan, Brussels, 1894; "The Orchid-Grower's Manual," by B. S. Williams, seventh edition, London, 1894, a large manual with numerous illustrations; and "Die Orchideen," by R. Schlechter. Berlin, 1914, 1915, a comprehensive handbook and manual giving the most recent taxonomic treatment of the cultivated orchids. Besides these larger works suited to the technical needs of the cultivator, a large number of popular works have appeared. Among these are: "Orchids for Everyone," by C. H. Curtis. London and New York, 1910, a beautifully illustrated popular handbook; "Woodlands Orchids," by F. Boyle, London, 1901, a popular account of orchids with stories of their collecting; "The Book of Orchids," by W. White, London and New York, 1902; "Culture, of Greenhouse Orchids," by F. Boyle, London, 1902; and "Orchids," by J. O'Brien, New York, 1911; "Our Native Orchids," by W. H. Gibson, New York, 1905, a popular account, with illustrations; and "Lilies and Orchids," by Rosina C. Boardman, New York, 1906,'contains color-sketches of seventeen native species. Among the works of a more technical and monographic character containing plates of orchids should be mentioned "The Orchids of the Sikkim-Himalaya," by Sir George King, Calcutta, 1898, 448 engraved plates (in "Annals of the Royal Botanic Garden," Calcutta, Volume VIII); "Icones orchidearum austro-africanarum extra-tropicarum," by H. Bolus, London 1893-1911, 250 partly colored plates with descriptions; "Orchidaceae," by O. Ames, Boston and New York, 1905, five fascicles giving illustrations and descriptions of new or recently described species which had been inadequately figured up to the time of the appearance of the work; and "Die Orchideen von Java," by J. J. Smith, Leiden, 1905-1914. one volume, text and one volume plates. Finally may be mentioned the work of F. A. Bauer, "Illustrations of Orchidaceous plants," London, 1830-1838, an account with thirty-five colored plates showing the structure and morphology of the various genera.
The illustrations accompanying the present article are in part borrowed or adapted from German sources, as follows: Figs. 2631, 2638, 2650, 2651, 2652, from Pfitzer in Engler & Prantl's "Die Naturlichen Pflanzenfamilien," II. 6; Figs. 2625, 2626,2627, 2630, 2632,2633, 2634, 2641, 2643, 2644, 2645, 2646, from Pfitzer in Grundz. einer Vergl. Morph. d. Orch., and Morph. Studien u. d. Orchideenbl.; Fig. 2653 from J. G. Beer, Betr. Morph. u. Biolog. d. Orch.; Figs. 2654, 2655, from Burgreff, Anz. Tropisch. Orch. Samen. Heinrich Hasselbring.
The general culture of orchids.
In the early days of orchid-culture, the treatment of the plants under glass was imperfectly understood, and with the meager knowledge of the natural conditions surrounding them in their native habitats, little successful progress was made for many years. The few cultural directions to be found were in works of foreign publication, scarcely applicable to plants grown in houses in America, where the winters are severe and changeable and the heat of summers more intense and less humid, necessitating a different mode of treatment. With a more satisfactory understanding of their requirements, orchid-culture here has made rapid advance in recent years, and most of the best collections have come into existence, many of which offer a very favorable comparison in fine well-grown specimens with those of the Old World.
Orchid houses and their construction.
Various are the opinions of cultivators regarding the proper construction of orchid houses to secure the best results. Forty or more years ago many fine specimens of orchids were grown without a special house, along with general stove and greenhouse plants, and many good plants are still found cultivated in this way, but where a general collection of orchids is grown, four separate houses or divisions will be found necessary to obtain the best results. These are known as the "East Indian," "Brazilian," "Mexican" and "New Granadan," or odontoglossum departments. This is the older terminology, but it represents a good cultural classification.
The East Indian department requires a winter temperature of 65° to 70° F. by night and 70° to 75° F. by day; a few degrees' rise with sun heat will do no harm. The temperature should be gradually increased 10° toward midsummer and gradually decreased toward late fall. This is the warmest house and is used for the cultivation of aerides, angraecums, the warmer tropical cypripediums, phalaenopsis, calanthes, dendrobiums and thunias while growing.
The Brazilian department should range in winter from 60° to 65° F. at night and about 70° F. in the day, allowing a few degrees more with solar heat, and a rise of 10° toward midsummer. This department is for bulbophyllums, cattleyas, warm epidendrums, Brazilian laelias, miltonias of the cuneata and spectabilis sections, Odontoglossum citrosmum, stanhopeas, and various genera and species requiring a like temperature.
The Mexican department is used chiefly for the cultivation of Coelogyne cristata, Mexican laelias, growing lycastes, anguloas and acinetas, many species of Maxillaria, a large part of the oncidiums and warm odontoglossums, phaius and allied species which require a few degrees lower night temperature and usually a little more sunlight to ripen their tissue for flowering than is afforded in the Brazilian department. It is also invaluable for resting dendrobiums and many other deciduous and terrestrial orchids.
The New Granadan (it might now be called the Colombian) or odontoglossum department must be kept as cool as possible in summer, and in winter should range from 50° to 55° by night and to 60° F. by day; it is used principally for masdevallias, odontoglossums. more especially O. crispum, and allied genera, disas, cool oncidiums, such as O. ornithorhynchum and O. varicosum, lycastes in warm weather, and many other individual species from high altitudes which require a cool house at all seasons for they suffer from the heat of our summer.
Styles of construction change, but the fundamental principle in building an orchid house is to secure a structure that can be easily heated and which has a naturally moist atmosphere without excavating deeply, for houses built much below ground lack circulation and almost always prove detrimental to orchid-culture. The houses (excepting the New Granadan house) should preferably be built to run north and south with an east and west exposure, in order that they may receive the benefit of the early morning and late afternoon sun, with the least possible heating effects from it at noonday, thus making little ventilation necessary; atmospheric moisture will be more easily retained in such a structure. The houses may be as long as required (with the potting-shed at the north end to avoid unnecessary shade and protect the houses in winter against severe north wind), and about 16 feet wide, which will allow side beds of 2½ feet each, two walks of the same width, and a center pit 6 feet wide. From floor to ridge should be 10 feet and to the eaves 4½ to 5 feet. Top ventilators should extend along both sides at ridge, thus affording protection from direct cold winter drafts in airing by using the sheltered side. Side ventilation is unnecessary and often injurious, the direct drafts causing plants which are out of condition to shrivel.
In glazing orchid houses, the. glass should not be less than 12 by 14 inches, and larger if possible. It is also important that only the best quality procurable be used, free from lenses which burn the leaves when shading is removed. Plate glass is much to be preferred when it can be had, as it contains no lenses and gives a pure even light. If this is used a size about 16 by 24 inches will be found very serviceable. Poor glass should not be employed in any case, as it necessitates shading long before this is beneficial to the plants.
The outside walls should be built of brick or stone when possible, and the beds and pits within should be of the same material, 8 inches thick and about 3 feet in height, filled solid to the top, using stone or rubble for drainage in the bottom, following it up with finer material and finishing with an inch or two of fine gravel. Wooden benches may be used if desired, often with first-class results, by covering them 2 or 3 inches deep with ashes, sand or gravel, but the solid benches are more sure to give better satisfaction. They give off moisture more gradually and offer a cool footing for the plant both winter and summer, which is essential and natural.
Good results will follow from either steam or hot- water heating when properly conducted. Unless the range of glass is large and a night fireman is kept, the old-fashioned method of hot water under natural circulation will be useful for orchid collections, using the regulation 3½-inch pipe, running the flows along the back beneath the eaves and returning along the floors beneath. (See Fig. 2656, which fairly illustrates an acceptably constructed house.) The quantity of pipe required for heating a house depends upon the location and degree of heat desired. A slab or board should be placed along the back of the side beds to throw the heat against the eaves and protect the plants from direct heat before it has assimilated the moisture of the house.
The New Granadan house should be a lean-to structure of northern aspect, with a wall of stone or brick along the south side to protect it from solar influence as much as possible (see Fig. 2657). The glass should be protected by canvas roller shades raised 15 or 20 inches above the glass on framework. One side of the canvas should be tacked along the top of the house, and the other to a round wooden roller 3 or 4 inches in diameter and as long as convenient to draw up; the two ropes should be fastened to the ridge, carried down beneath the shade around the roller, and up over the top to a single pulley near the ends; thence through a double pulley in the center and down over the top of the shade to the ground. By these ropes the shade can be raised and lowered in cloudy and bright weather at will. (See Fig. 2658.) Solid beds and piping similar to the other orchid houses can be used, or as in Fig. 2658; viz., a flow and return down each side connected with valves so that either or both sides may be used as desired.
Shading of some sort on the glass is necessary for all orchid houses from early February until November, and in some cases also in the winter months, to protect the plants from the sun. It may be of canvas, as in Fig. 2659, or consist of whitewash or paint applied directly to the glass. Whitewash made from fresh lime is perhaps the best to use, as it is easily removed in autumn. The first application in February should be light, following it with a second coat a month later, and, if necessary, a third in July. This will wear off gradually and in most cases should be entirely removed in December. It is easily removed with a stiff brush. There are also patented shadings.
The two great horticultural groups.
Orchids are horticulturally divided into two large sections: terrestrial and epiphytal, the former embracing those that grow on the ground and derive their nutriment more or less directly from it; and the latter those that usually attach themselves to rocks and trees, and derive a greater portion of their nutriment from the atmospheric gases and accidental deposit of decaying leaves, or grow among the various ferns and vines, which grow in abundance on the rocks and trees of the moist, wooded tropics, absorbing the various elements of their slowly decomposing humus.
Terrestrial orchids grow at various altitudes, and are widely distributed throughout both hemispheres, the polar regions and arid deserts excepted. Many are deciduous and tuberous-rooted; some grow from underground rhizomes; others are pseudobulbous and deciduous, while not a few have reed-like stems. Examples of terrestrial orchids are catasetum, calanthe, cyrtopodium, most cymbidiums, some of the cypripediums, disa, goodyera, govenia, habenaria, lissochilus, many masdevallias, microstylis, neottia, orchis, pogonia, peristeria, phaius, sobralia, spathoglottis, all of which should be sought under their special genus headings in other portions of this work for cultural directions. They differ very essentially in structure, and in many cases require a special method of treatment for individual plants of the same genus, as Habenaria for example, where some are found growing in rich, turfy loam exposed to sun, while others inhabit wooded, swampy locations.
Many species of terrestrial orchids nearly or quite defy successful treatment under cultivation from lack of knowledge regarding the mineralogy of their native habitats, or from the plants being practically saprophytic on certain species of decaying vegetation, or growing only in connection with the mycelium of special fungi, which may assist them in making proper growth.
The hardy species, when a general collection is grown, should be cultivated in pots in coldframes, as many need protection during winter and others require shade which can be supplied by painting the glass. Our native hardy species, however, do best planted out in a properly constructed rockery, laid out in pockets so that each may receive its proper compost.
The more tropical species—cymbidiums, cypripediums such as C. insigne, Phaius grandifolius, P. macu- latus and P. Wallichii, sobralias and some other evergreen species—thrive best in the Mexican or cool end of the Brazilian house.
Anaectochilus, tropical goodyeras and cypripediums, spathoglottis, and several genera of like nature, require the same general treatment as epiphytal orchids, with temperature of the East Indian department at all seasons.
Bletias, catasetums, cyrtopodiums, calanthes, many lycastes, tropical liparis and microstylis, Phaius Humblotii and P. tuberosus, thunias and many other deciduous and semi-deciduous species, should be grown in the East Indian, or warm end of the Brazilian department, and during the resting period should be placed in the Mexican department, allowing them only sufficient water to keep the plants in sound condition.
Epiphytal orchids are found chiefly in the humid forests of tropical countries, often along streams where they receive their moisture in the dry season. A few grow in open grassy situations or among brush. These consist chiefly of climbing epidendrums of the E. evectum section, a few oncidiums of the caulescent type (the distance between the pseudobulbs often denoting a year's growth), and some of the terete vandas, and others.
Aerides, phalaenopsis, vanda and the epiphytal cypripediums are distributed throughout India, Malay Peninsula, Cochin-China, Celebes, Borneo, Philippine Islands, Java and some of the Oceanic islands, usually following the moist forests of mountain ranges, occasionally at high elevations. With one or two exceptions, as Vanda caerulea, all do satisfactorily in the East Indian department, reserving the warmest part for phalaenopsis, which, as a rule, grows nearest the sea-level.
Angraecums are natives of Madagascar and tropical Africa, with one isolated species, A. falcatum, which is from Japan. They grow in humid, shady locations, where they can receive a copious supply of water at all seasons, and are closely allied to vanda, requiring the same general temperature and treatment.
Dendrobiums are most common throughout India, Moulmein being a central district, but they are also plentiful and widely distributed throughout eastern Australia, New Guinea, the islands of the west Pacific and Oceanica under various climatic conditions. The larger part of them, especially the deciduous species, are subjected to long droughts and long resting periods, but as they lose their foliage at that time their evaporating surface is reduced to a minimum, and the effect of the dry heat through the day is more than counteracted by heavy dews and the condensing vapors which arise in the early mornings in those countries.
Bulbophyllums and coelogynes have their homes principally in the mountainous forests of East India and Borneo, where they are copiously supplied by frequent rains. Nearly all grow best in the Brazilian department.
Cattleyas and felias inhabit the humid forests of the various mountain ranges of tropical America, from Mexico south through Colombia to Peru, the North Amazon Valley, through Venezuela and Guiana, and the mountain belt of eastern and southern Brazil, usually at an altitude of 2,000 to 5,000 feet, excepting the Mexican species, L. albida, L. anceps, L. autumnalis and L. majalis, which grow at 5,000 to 8,000 feet, commonly among polypodium fern.
Cattleyas and Iaelias grow on rocks and trees often devoid of other vegetation along the margins of rivers and ravines, usually in shade, where they receive a copious supply of water from heavy dews and condensation of morning fogs which saturate the forests during the dry season, and often excessive rains while growing. They should be grown in the Brazilian department, excepting Cattleya citrina, the Mexican Laelias and L. Jongheana, which thrive best in the Mexican department or warm end of the New Granadan house.
Stanhopeas are found from southern Mexico south to Peru, Venezuela, Guiana and Brazil at rather low elevations, often in dense forests, the individual species having a very wide range. The Brazilian house affords them the best temperature, but they may be grown in any of the departments with success.
Epidendrum is a large and varied genus, widely distributed throughout tropical America and in the United States from South Carolina southward, and one of the few epiphytal genera inhabiting the United States. They are found at all elevations from sea-level to 10,000 feet or more. The writer found E. ibaguense growing in quantity on the margin of perpendicular clay ridges fully exposed to the sun at this altitude in the United States of Colombia in a robust, healthy state, and the same species below 5,000 feet in the same condition. Many of the individual species cover a wide range of distribution. They require the same general treatment as laelias and cattleyas. Few species are worthy of cultivation except for botanical purposes.
Maxillarias cover much the same range as the last genus, but are not quite so widely distributed. They grow equally well in either the Brazilian or Mexican departments.
Oncidiums are distributed along the mountain ranges from southern Mexico to Peru, in the southern and norther portions of Brazil, chiefly along the coast, the Spanish Main and islands of the Caribbean sea. The O. carthaginense and O. Papilio sections are found at sea- level and seldom above 500 feet elevation. These grow best in the Brazilian house. Nearly all of the other species may be grown in the Mexican department, except a few, such as O. cucullatum, 0. Phalaenopsis and the O. macranthum section, which are found at high altitudes; these should be grown in the New Granadan department.
Odontoglossums follow the higher wooded mountain ranges from southern Mexico, Central America and the Central Andes of Colombia south to Peru and the northwestern portion of Venezuela, all at high altitudes.
They usually grow in the moist shady forests, where the rainy season is long continued or condensing fogs and dews are very heavy, keeping many of the species in an almost perpetual state of saturation, their only relief of excessive moisture appearing to be from the frequent heavy winds that prevail in these regions. The Mexican species grow well in the cool end of the Mexican department, while those of the O. luteo-purpureum and O. crispum type require the New Granadan house.
Lycastes are distributed from southern Mexico to Peru along the mountain ranges, usually at an altitude of 4,000 feet in rather shaded locations; they are most common from southern Colombia to their northern limit. L. tetragona is from southern Brazil and far removed from the general area of distribution, with little resemblance to any other species. Its 4-angled monophyllus pseudobulbs produce semi-pendent scapes carrying often as many as eight flowers, not unlike a cympidium hi general appearance. Lycastes grow well in either the Mexican or New Granadan department.
Selenipediums are the South American representatives of cypripedium. They are distributed from Costa Rica south to Bolivia, through Venezuela, Guiana and eastern Brazil, from 3,000 to 8,000 feet elevation, in wet marshes and on the branches of trees in shaded forests, in all cases where they get a bounteous supply of water at all seasons. The Brazilian or Mexican department suits them equally well.
Masdevallias, restrepias, and pleurothallis grow at high elevations in Venezuela, Mexico and south to Peru, with a few in the Organ Mountains of Brazil, their principal center being Colombia near the odontoglossum district. They always follow the mountain ranges, growing on trees, rocks and on wet, marshy slopes, in extremely wet locations. The chimaera section is found at the lowest elevation. They all grow best in the New Granadan department.
Newly imported orchids.
On arrival of cases of orchids from their natural habitats, they should be carefully unpacked as speedily as possible, in an isolated room where insect pests that often arrive in the cases may be destroyed, and laid carefully and loosely against one another, on the bench of a shady well-ventilated house or packing-shed. Should they all be found in good condition,' the pseudo-bulbous species, such as cattleyas and laelias, should be hosed over thoroughly and allowed to remain for about a week, at the end of which time they should be examined for any signs of decay and bruises. All such parts should be removed with a sharp knife. The plants should be cleaned and sponged to remove dust, potted or basketed, as the case requires, and placed in a shady portion of their respective departments, allowing them sufficient water gradually to start them into action, after which time they will require the same treatment afforded established plants of their kind.
Cypripediums, masdevallias, phalaenopsis, vandas, the batemannia and bollea sections of zygopetalum and other non-pseudobulbous genera should be placed on damp sphagnum in a well-shaded airy department for a week or ten days, without syringing, until it is ascertained what amount of damage they have received in transit. After sponging the leaves carefully and removing any decayed and bruised parts, they may be potted and basketed, and removed to their proper quarters, watering sparingly until they start new action.
It is customary in some establishments to hang newly imported orchids by the roots, tops down, from the roof of the house or beneath the benches until they show signs of new action, but they invariably suffer more or less from this practice and are better treated as above.
Pots, baskets, and supports.
Many orchids are best cultivated in the ordinary earthen pots and pans, more especially terrestrial species and a few of the epiphytal kinds, which grow on rocks in marshes, and among quantities of humus and fern roots. Most of the epiphytal species, however, need special structures that will admit air to circulate freely to the roots; otherwise, these are liable to decay through excess of water if confined in close pots when inactive in winter, which must eventually weaken the constitution of the plants.
The best and most practicable pots and baskets are shown in Figs. 2660 to 2661. Fig. 2660 shows the orchid basket most commonly used; it is the best adapted for the general culture of cattleyas, coryanthes, dendrobiums, epidendrums, laelias, masdevallias of the chimaera section, oncidiums, and most orchids with pendulous flower- scapes. They may be made of cedar, teak-wood, cypress, or any durable wood. The wood is cut into square (or round) sticks of any length desirable and in proportionate thickness from½ to 1 inch, and carefully perforated at each end. Through the holes is inserted a strong wire, which is looped at the upper end when finished in order to receive the wire hanger. These baskets may be as deep as desired, but three sticks on each of the four sides are usually enough for most orchids, with two or three placed crosswise through the bottom, to hold the compost. The hanger is made by twisting together and bending down in the middle two pieces of galvanized or copper wire, thereby forming four ends to insert in the basket- loops and a loop or hook at the top by which to suspend it.
The orchid cylinder (Fig. 2661) is very useful for standing on the bench or pit, and is used for renantheras, aerides, vandas, angraecums, epidendrums, and many other tall plants that are too tall or difficult to suspend. Cylinders are made in all sizes and any diameter desired, with either square or round sticks. They are bored a short distance from the ends and a wire inserted through them, with a small block between each stick, to make an opening for air. When large enough the sides are brought together and fastened. The depth is adjusted by movable cross-pieces.
The orchid raft (Fig. 2662) is made in much the same way as the cylinder, but is left flat with the openings between closer together. Oblong-square blocks of hard, rough wood, an inch or less thick, answer much the same purpose. The orchid raft or block is very useful for many species, such as Cattleya citrina, barkerias, Epidendrum falcatum, Dendrobium Jenkinsii, Oncidium Limminghii and O. Papilio, scuticarias and the like.
The earthen basket (Fig. 2663) is useful when the compost is fine and when the roots do not require much atmospheric action; also properly to mature tissue in a few terrestrial species, thereby inducing them to flower more freely. The earthen basket is especially useful for acinetas, peristerias with pendulous scapes, stanhopeas and others; it is made with ovate openings around the sides and a round one in the center to admit pendulous scapes.
The perforated pan (Fig. 2664) is usually made only in small sizes and used for bulbophyllums, the concolor type of cypripedium, dendrobiums, and many other small-growing species that do well suspended from the roof.
The perforated orchid pot (Fig. 2665) is for bench use ana is useful for many epiphytal orchids that are not to be suspended, the perforations or holes supplying abundant air to the roots, a safeguard against losing them through overwatering in winter.
Figs. 2666 and 2667 show the standard earthen pot and pan for terrestrial species. They should have the drainage holes made on the side at the base, instead of directly underneath, as a preventive against earthworms entering from the benches.
Potting of terrestrial orchids.
Terrestrial orchids as a rule grow best under pot culture. Potting material for the following genera— acanthephippium, bletia, calanthe, cymbidium, Cypripedium insigne and most of the hardy species, cyrtopodium, habenaria, liparis, microstylis, peristeria, phaius, pleione, sobralia, thunia, and some others—should consist of about one-third each of chopped sod with some of the fine soil removed, chopped live sphagnum and leaf-mold, adding a little ground bone for some of the strong-growing kinds. One-third of the pot space should be devoted to clean drainage, covered with sphagnum or rough material to keep it open. After removing all decayed parts, the roots should be carefully distributed and the compost worked in gently but firmly around them, leaving the surface a little convex and slightly below the rim of the pot as in Fig. 2666 (the dotted lines denote drainage required). The convex surface gives the rhizome an opportunity to dry out frequently, thus avoiding fungi, which are troublesome to some species.
In repotting terrestrial orchids, sufficient pot room should be given to last a year or two if possible, as they dislike to have their roots disturbed oftener than is necessary. The best time to repot is just before the rooting period, or when they are starting their new growths in spring. The deciduous species of calanthe can be easily increased at this time, if desired, by removing the old bulbs and placing a number together in a pan or shallow box, covering them partly with compost and placing them in a warm house until they start action, after which time they should be potted as desired, two or three together.
Anoectochilus, arpophyllums, cypripediums, disas, goodyeras, spathoglottis, and many allied genera, grow best under pot culture, but otherwise require compost and treatment similar to the epiphytal kinds.
Potting, basketing, and compost for epiphytal orchids.
The roots of epiphytal orchids are usually very porous, and many are covered with a corky substance (velamen), capable of absorbing and retaining water for considerable time. In their native homes a great many of the roots are aerial or grow in loose, fibrous material, such as moss and the fine roots of polypodiums and other ferns, where they have free access of air at all times. It is important that they receive similar treatment under cultivation so far as is consistent with the difference of their environment taken into consideration. Thus it is apparent that one of the special features in the culture of epiphytal orchids lies in the proper selection of compost and the method of potting and basketing for the best results in after-cultivation.
Peat fiber, sphagnum moss and leaf-mold constitute the principal materials of good compost, usually lasting one or two years without renewal, which is important, as the roots suffer more or less in being disturbed. By peat fiber is meant the fibrous roots of various wild ferns, with the fine soil removed by first chopping it into small pieces, then rubbing it across a coarse sieve. The several species of osmunda furnish us with the best orchid peat. (See Osmundine, page 2414.) The sphagnum moss used for orchids should consist of Sphagnum squarrosum, S. macrophyllum and the coarse-leaved species only; S. acutifolium and other weak-growing species should never be used, as they soon decay and are detrimental to the roots.
Leaf-mold is made from decomposed leaves. The leaves of almost any tree will do, but those of hardwood trees are most desirable, especially oak. When collected in the fall the leaves should be heaped up to decay for a year or more, and turned over at least twice within that time.
Charcoal is the best material to use for drainage and for mixing or interspersing with the compost. It is best made from hardwood and should not be over- burned. Broken potsherds are often used, but they are not so good; being porous, they either absorb too much water at times or become over-dry too often and are liable to prove injurious. Charcoal is lighter in weight, and contains more useful properties.
Where closed pots are used , nearly one-half of the space should be devoted to drainage and the remainder to compost, consisting of about equal parts of peat fiber, chopped sphagnum and leaf-mold for most genera, adding a few pieces of charcoal in potting, and a piece beneath the rhizome of the tender ones. Care must be exercised in potting to distribute the roots properly and make the compost moderately firm about them, leaving the finished surface convex, to throw off surplus water and protect the rhizome from an overabundance of wet. Top-dressing with live sphagnum is beneficial to many orchids, such as Odonioglossum crispum and allies, and gives the surface a neat appearance. Fig. 2668 illustrates a finished pot, the dotted line in Fig. 2666 indicating the amount of drainage required.
When perforated or open-work pots or baskets are employed, no direct drainage is necessary. Rough, broken pieces of charcoal should be freely used in the compost while potting, as it helps to keep the mass firm and the roots of nearly all species attach to it freely; also it lessens the quantity of compost and so modifies its texture as to allow it to dry out more readily than when packed in a solid body.
Cattleyas of the C. intermedia type, coryanthes, cypripediums of the C. Lowei and C. Stonei sections, some dendrobiums, Oncidium carthaginense, O. crispum, O. macranthum, 0. Papilio and their allies should have the leaf-mold omitted, while aerides, phalaenopsis, saccolabiums, vandas and kindred genera require only chopped live sphagnum and charcoal as a compost.
Watering, humidity.
It is impossible to lay down any hard and fast rules for watering orchids. Watering is a very important operation and requires more or less practical experience, connected with a knowledge of the general conditions surrounding the plants in their native homes. As a rule, most orchids need a liberal supply while growing, but the condition of the plant ana compost and the manner in which it is potted or basketed have much to do with this.
The evergreen terrestrial species, which grow chiefly in loam fiber, as cymbidium, Cypripedium insigne, phaius, sobralias, and others, require water whenever the surface of the compost is becoming dry, with occasional light overhead syringing in fine weather, which will assist in keeping down red- spider, thrips and other pests. An occasional application of weak liquid cow- or sheep-manure is of great benefit while the plants are growing.
The deciduous species have a decided period of rest, at which time they are practically inactive and need very little water, enough only to keep the stems and pseudobulbs in sound condition. When growing, however, they require a good supply and should have a thorough watering to the bottom whenever the soil is becoming dry, out should not be kept hi a wet condition at all tunes, or the soil soon becomes sour and infested with worms, under which condition no orchid can do well.
Epiphytal orchids, or a greater part of them, in their native habitats grow in locations where heavy rains are frequent or of almost daily occurrence in their growing season, and where condensing vapors settle on them like dripping rain, while the early morning fogs rise among the forests, charging the atmosphere almost to saturation in the early part of the day in the resting season. Such species as are subjected to a severe dry resting season are often deciduous (see Dendrobium, and also, page 2393). Many of the extremely alpine species, such as the masdevallias and Odontoglossum crispum, are subjected to two annual rainy seasons, and where these seasons are much prolonged it has been observed that the last-mentioned species in its native habitat mature as many as three pseudobulbs in the year. Thus the pseudo- bulb is no indication of annual growth, but a reservoir of supply in case the plant is overtaken by severe or sudden droughts, each pseudobulb being supplied with a mature secondary bud for further reproduction should the proper lead be destroyed.
Such genera as aerides, cypripediums, masdevallia, vanda, and the like, which have no pseudobulbs, rely more or less directly on a daily supply at all seasons. These, with many of the extreme alpine species, should have a liberal supply of water at all times.
Many of the pseudobulbous kinds, including cattleyas and laelias, are also constantly in action perfecting new roots or maturing their flower-buds, after the pseudobulbs are completed and they are apparently at rest. For this reason careful observation of each species is necessary to make their cultivation successful.
Under basket culture, there is least liability of injury through overwatering, and excepting kinds like the oncidiums and dendrobiums (which need a dry and cool resting period to induce them to flower), and deciduous species at rest, nearly all should receive a good supply of water, weather permitting, whenever the compost is becoming dry, with frequent syringing overhead in fine weather, when the temperature is normal and ventilation can be given. A stimulant of weak sheep- or cow-manure applied occasionally to plants in action will benefit them.
On cold, cheerless days, when the temperature is below normal and the atmosphere is overcharged with moisture, very little watering or damping is needed, and unless it be some particular species which cannot endure drying, or tiny seedlings, it is safest to withhold water, as at these times the stomata cease action and the plants become overcharged with water; thug those with weak constitutions and immature growths are liable to attacks of wet-spot and rot. The best means of counteraction in such cases is to apply fire heat and ventilation. A close stagnant atmosphere is always to be avoided. As a safeguard against excessive changes in humidity, a hygrometer should be kept in each department to ascertain and regulate the degrees of moisture, especially during fall and winter. When overabundant, moisture can be reduced by applying fire heat and ventilation, and if insufficient by wetting down the paths and shelves, or pits, and reducing the ventilation. Well regulated departments should be kept as near as possible to 70° or 75° through the day or 80° to 85° with free ventilation, and about 80° at night. Just after damping and watering, it will often rise to 85°, but this is of no consequence, as it soon recedes. Orchids at rest, such as calanthes and dendrobiums, should be held at 65° to 75°. In no case, where it can be avoided, should it go below 60° nor rise above 90° for any length of time, as serious results are very liable to follow.
Ventilation.
The ventilators should extend the entire length on both sides of the ridge, and be supplied with the best modern lifting apparatus. Extending them continuously along the roof necessitates raising them but a small height to afford proper circulation to the plants and egress of overheated air, without losing too much moisture. Having them on both sides assists in avoiding direct drafts, by using the side protected from the direct wind.
Air must be given at all times, when possible, to keep the atmosphere active, as well as to lower temperature, also to reduce the density of moisture when excessive in close, inclement weather and during the night. In bright weather ventilate enough to allow egress of the heated air.
It is customary with some cultivators to close down ventilators in wet weather and during the night to help retain heat. This is a serious mistake. It may show no visible injury in bright weather, when the density of moisture in the atmosphere is at a minimum, but this bad practice surely accounts for the decaying of many young growths, which are lost during wet, close and cloudy nights.
Propagation.
Many species of orchids can be propagated by division and by cuttings. This is usually resorted to when it is desired to increase the stock of rare and unique species and varieties. With the more common species, however, it is cheaper and better to buy freshly imported stock, if it can be had, as it often requires two, three or more years to bring the young plants to the flowering stage.
The pseudobulbous species, such as cattleyas, odontoglossums, coelogynes, are propagated by cutting part way through the rhizome three or more pseudobulbs behind the lead with a sharp knife. This will usually retard the sap and force the dormant eye behind the cut to grow. The back portion may then be removed and potted or basketed separately, or left on the plant to mature the new growth, and be removed when it starts action the following season.
With the deciduous calanthes, the old bulbs should be removed when potting them in spring and put, several together, in pans or flats and partly covered with sphagnum or potting compost until they start to grow, when they should be potted in the regular way. Thunias are easily propagated after the young growths are well advanced, by cutting the last year's stems into pieces 4 or 5 inches long and inserting the ends hi chopped sphagnum and sand, placing them in the propagating-house until they grow, when they may have their normal heat. Dendrobiums are managed in much the same way, or the old canes can be laid on wet sphagnum, when many will produce new growths from the side eyes on the nodes. Aerides and vandas are increased by removing the upper portion with a sharp knife, leaving a few roots and at least a foot of stem to each top. The old bases of the stems usually break new growths freely, often producing several new shoots from each. Cypripediums should be divided between the older growths, leaving at least one old growth with each lead; and potted separately, allowing them a little extra moisture until they start to grow. Masdevallias and allied genera can be separated in the same manner, leaving several leaves and one or more new growths or leads to each piece. All species should be propagated at the commencement of the growing season.
Reproduction of orchids from seed.
The reproduction of orchids from seed through crossing and hybridizing has been conducted for many years successfully by a limited number of hybridists, principally abroad, and it is only within about twenty - five years that it has received much attention in America, but in that time very many beautiful hybrids have come into cultivation. Many of our establishments, both private and commercial, are now paying much attention to this branch of orchid culture, with varying degrees of success.
The seeds germinate nest when sown soon after maturity, and many lose their vitality in a few months if kept too dry and warm. When sowing the seeds, the best results are often obtained when they are dusted on the surface of pots or baskets containing a plant of the same genus as the seed and carefully watered with a very fine rose until they become attached, watching carefully for snails, slugs, and depredators in general that infest the compost. The pots or baskets should have a favorable-looking surface, with the compost in good condition, firm and free from fungi. Use pots or baskets that will not have to be disturbed for a year or more, as it often takes that length of time for the seedlings to come through. Seed sown in early spring seems to germinate soonest. The writer has had selenipedium seedlings up in three months from sowing, and again has waited for cypripedium twenty- three months before the seedlings appeared.
After the seedlings have perfected two or three leaves it is quite safe to remove them to small pots, singly, or several to a small pan, using compost of the same material as that for the parent, but cut a trifle finer. Many tiny seedlings are lost shortly after germinating, through the soil becoming sour or through fungi. When thus attacked they should be transferred to other pots or baskets not infested.
A newly germinated seedling of Phaius hybridus is shown in Fig. 2669. Fig. 2670 is of a three-months-old seedling of Cypripedium insigne var. Sanderae, in proper condition to be transferred to a pot; Fig. 2671, eight-months-old plant of Phaius Wallichii; Fig. 2672 a twelvemonths-old hybrid cattleya (C. intermedia x C. labiata)- Fig. 2673 a 2673. Thirteen months from seed. Cypripedium thirteen (Cypripedium.) months old; Fig. 2674 a two-year-old hybrid between a cattleya and Laelia (C. intermedia x L. praestans).
The raising of orchids from seed should be encouraged, and should enlist the energy of every orchid-culturist, not necessarily for the production of hybrids, but also for the reproduction of rare species and varieties, and to save a number of species that are fast decreasing or becoming extinct in their native homes. Aside from the financial inducement offered the commercial grower, it will prove instructive to the botanist and afford pleasure and pastime for the amateur.
Diseases.
Orchids are subject to many diseases. Those having importance from a cultural standpoint and most troublesome to the grower are known as wet-rot, dry- rot and spot. Wet-rot is brought on by an overmoist or stagnant atmosphere, and is usually first detected by a semi-transparent appearance of the parts affected, which soon become dark brown. It spreads slowly along the tissue. If noticed at the commencement it can be readily checked by slitting the epidermis with a sharp knife and removing the plant to a more airy position in the house for a few days.
Dry-rot is caused by a fungus which attacks the rhizome of the plant. It is often produced through burying the rhizome or base of the plant with compost. Cypripediums are subject to it. Large, healthy growths when attacked quickly show a sickly pale color in the foliage, which, on examination of the base, will be found discolored, and with a light brown appearance. If the portion attacked is quickly removed with a sharp knife it will usually give no further trouble; otherwise it will travel through the entire rhizome and destroy the plant in a very short time.
Spot comes from various causes: the appearance of small dark brown spots on the succulent leaves and pseudobulbs is usually an indication of cold and over- watering. Spot also arises through weak tissue, especially in phalaenopsis, saccolabiums and angraecums during winter, which have been grown too warm, shady and moist. The affected parts should be slit with a sharp knife and a little flowers of sulfur should be rubbed over the wound. When they make new growth the plants should be placed in a brighter and more airy position to induce a better growth. The brown dots which make their appearance on the leaves, especially at the apices and on new growths of deciduous and plicate-leaved species, indicate either lack of sufficient water at the roots or an over-dry atmosphere, both of which conditions can be easily changed.
Snails and insects.
Orchids are attacked by many forms of snails. Insect pests are a great annoyance to the cultivator. They can be kept in subjection only by constant attention. Slugs and shell snails are very destructive. If allowed to increase they devour young shoots, roots and flower- buds. The best means of capturing them is to place saucers of dry bran on the shelves among the pots, and look them over morning and evening. By this means many will be destroyed. Various species of scale insects attach themselves to the leaves, pseudobulbs and rhizomes of nearly all species of orchids, and can be eradicated only by the use of a soft brush and washing with a sponge and water. A little whale-oil soap added to the water is of great assistance, and also useful in destroying red-spider, green-fly and yellow-fly. Black and red thrips attack the young growths of many species and often become very troublesome. Fumigating the houses with tobacco stems lightly about three times during the week will soon cause them to disappear. Fumigation is also a sure remedy for green-fly.
The cattleya fly is very injurious to young growths of cattleyas, laelias and some epidendrums. The flies lay their eggs in the very young growth at the base, causing an enlargement which is easily distinguished. The only remedy is to remove the growth and turn it. The mature fly can be eradicated by fumigating the house with tobacco stems about three times each week during early spring.
The dendrobium beetle larva burrows in the stems of various species of the genus, and is detected by a small discolored spot. There is no remedy, except to cut away and destroy the parts attacked. A pest much more to be dreaded is the dendrobium mite, which perforates the canes and rhizomes of dendrobiums and many other orchids, laying a number of eggs in each perforation. On hatching, these eat away a part of the plant around them, causing that portion to decay. They can be found only by careful and close observation, and this often after the plant is beyond redemption. There is no remedy but cutting them out, and unless the plant attacked is valuable it is best to burn it and keep the pest from spreading.
Mealy-bug is usually not very troublesome to orchids. It is readily seen and destroyed without much injury to the plant.
Roaches are usually very troublesome, and hard to eradicate, as they feed at night and remain hidden through the daytime. They destroy roots, growing shoots and young flower-buds and scapes. Bran, powdered sugar and paris green, mixed together and placed around the houses in saucers, will usually keep them in subjection, and they should be hunted down at night by the aid of a lantern. Many can be caught in this manner.
Sow-bugs or wood-lice are usually common in every part of orchid houses, pots and baskets. They do a great deal of damage to young leaves, roots and the tender portions of flower-scapes. The paris green mixture used for roaches is very effectual in reducing their number, but it is impossible to be entirely freed from them- Robert M. Grey.
Hardy orchids.
Many of our native species of orchids are very beautiful, and some are easy of culture, given suitable situations as to soil, moisture, and, in some instances, shade. It seems almost impossible to tame these wildlings, in the sense of making them border plants; the desirable situations are shady moist places in the woods for the habenarias, Galeorchis (Orchis) spectabilis, listera, and goodyera. Moisture, however, does not mean a stagnant condition of the soil, but slight depressions that are preferably above the level of surrounding soil, so that drainage is secure.
The two-leaved habenarias, such as H. Hookeriana, H. orbiculata, H. blephariglottis, and H. dilatata, all occur in shady woods. One seldom finds more than an isolated specimen or two, but these may be easily transplanted after their flowering period, taking care to keep the fleshy tuber-like main root intact. H. psycodes is a bogplant and is often found in colonies, and this species is widely distributed. H. ciliaris grows in bogs in great numbers, and, when in bloom, thebright orange-colored flowers make a beautiful display in late summer. H. fimbriata is also a very showy bog-plant, enjoying the full sun. The arethusa often colors New England wet pastures a bright rose-purple in early summer where it is found in quantities very unusual in orchids; it requires very careful handling in digging when transplanting. Some of the soil should be dug with the plant to ensure its growing, and the same is true of the calopogon and pogonia, which also have pretty pink or purple flowers. Good success has been had in establishing colonies of goodyeras on shady banks; the three species, G. repens, G. pubescens, and G. Menziesii, which are very common in the North woods, have beautifully variegated leaves prostrate on the ground, and when in bloom are as pretty as the spiranthes, and a colony can readily be established.
The species of spiranthes are also easy to naturalize. It is found, however, that these plants appear to bloom biennially; one season the dry fields will be dotted with the pretty white flower-scapes, and the next year not one is visible. They have been dug in large numbers, but do not bloom the next year; it seems they require a year in which to recuperate. The common species are Spiranthes gracilis and S. cernua, both very easily naturalized, as the roots can be dug with a little soil attached. Aplectrum hyemale found but rarely, is easy of culture and transplanting, owing to its having bulbs like many exotic species. The bare flower-scape arises in early summer, and afterward a single broad evergreen leaf appears to mark the place. Liparis liliifolia also has fleshy bulbs above the ground, is easy of cultivation and when the purplish lipped flowers are open, a little colony is very pretty and interesting.
The cypripediums are the best known and most sought of native orchids, C. spectabile is becoming rare and more difficult to get, but there are plenty of places in the remote North woods where it is still found in quantity. This plant is usually regarded as a bog habitant, but it occurs also on the slopes of shady ravines. C. pubescens is found in the same situations, and C. parviflorum, the smaller yellow species, is a bog-plant. All these are easy of cultivation if moisture is secure. They are found at tunes where it seems to be very dry at the roots, but an examination proves that there is seepage from above that provides the necessary moisture, and gives a clue to their culture. In the ravines on the shady slopes, cypripediums reproduce themselves from seeds to a greater extent than is supposed under cultivation, and the pretty yellow and pink flowers are much admired and sought. C. parviflorum is exceedingly fragrant when in bloom. C. acaule, the common red-and-brown species, is not so tractable, but on sloping banks in partial shade they have flowered for two years and seem to be established. Two other species, C. arietinum and C. candidum, are hard to obtain, and more difficult to grow than the others, but with care and study of their natural conditions, it is probable that success may be attained with them. There are several Pacific coast cypripediums that have not proved tractable. Possibly they are hardy in the East under proper conditions; this is the case with Epipactis Royleana, and C. californicum and C. montanum are valued in gardens abroad. There are also some fine new species from China and Thibet that give promise and have flowered in Massachusetts gardens from roots brought home by Wilson. We may yet see these widely distributed. There seems to be no recorded example of hybridization among our native cypripedes; it has been attempted many times, and it is strange, in the light of the numberless crosses made among the exotic species, that ours remain true even to themselves, and cannot be mixed.
There are many small gardens in which the study and culture of hardy orchids might well be taken up, together with that of the ferns. The same conditions might be made ideal for both in a very limited area. It is essentially an occupation for the amateur, for the idiosyncrasies of the plants are many. One must have the liking for exploration of the woods and bogs where the plants grow, and preferably gather the roots oneself. In no other way can the special requirements of each species or even each individual be studied and met. E. O. Orpet.
The culture of epiphytal orchids in Florida.
The greatest trouble in the cultivation of epiphytal orchids on trees in southern Florida is in getting them completely established in their positions on the branches or trunks. In a natural state, the seeds of orchids, which are exceedingly fine, are carried largely by the wind and scattered over the trunks and branches. Those that alight in suitable places germinate and send their roots over the surface of the bark and in time become flowering plants. In artificial culture the plants already grown are placed on the trees, and unless this is done right and they have proper care for awhile, until they become established, but few will live and do well. Indigenous orchids are very abundant on the trees in the hammocks of south Florida, both species and individuals, there being known at present not less than twenty native species in this region. One of these, Epidendrum conopseum, ranges throughout the northern half of the state and into South Carolina, Georgia, and Alabama. Another species, E. tampense, is distributed over most of the peninsula, and these are endemic. The others are confined to the lower part of the state and are found in the American tropics.
Strong, healthy plants should be chosen and the potting material cleaned out from the roots as much as possible. The roots should be spread put, and a little sphagnum placed over them; then drive a small nail through a strip of mosquito-wire netting and into a tree where it is desired to place the orchid. Then place the roots of the plant against the tree close to the nail, adjust the strip tightly over them and nail through it into the tree on the other side. It may be best to put a second strip across, as it is absolutely necessary that the plant be firmly fastened, for if it is at all loose it never will do well. It should be watered at the time of planting and at intervals of a day or two, if the weather is dry, until it is established.
Orchids should be put on trees that have firm bark which does not scale off. Live oaks are ideal trees and red bay (Persea carolinensis) is good. They may be placed on smooth-barked trees but the rough-barked are preferable. Wild rats are often abundant and when orchids are placed on sloping or horizontal surfaces they destroy the plants; therefore, fasten the plants to vertical stems. They may be grown in high or low hammock or on cultivated trees; in fact, in any location where the air is not too dry or the plants are not too much exposed. They may be kept in pots of leaf-mold under a slat-house.
Sometimes orchids are attacked by what is apparently a fungous disease, which operates suddenly and fatally. The sheaths, pseudobubs or leaves at first become almost semi-transparent, looking as if they had been frozen; then they turn brown and the plants die. So far, dendrobiums have not been attacked but cattleyas and the thick-leaved oncidiums have suffered greatly. If noticed before the disease has progressed far, the sheaths of the leaves should be stripped off, the plant sprinkled with water and well dusted with sulfur, and if this is washed off by rain, applied again.
The coolhouse orchids have totally failed after repeated trials. But most of the cattleyaa, the dendrobiums, oncidiums, epidendrums, lycastes, maxillarias, brassias and brassivolas, gongora, laelia, miltonia, vanda, cyrtopodium and others have succeeded excellently. Phalaenopsis amabilis and P. Schilleriana are succeeding excellently on trees in low hammock and bloom beautifully every winter. With cypripediums, cymbidiums, phaius and some other terrestrial orchids in the hammock, the success has been only moderate.
Epidendrum tampense is an attractive native orchid and well worthy of cultivation; E. nocturnum and E. cuculatum are interesting; Cyrtopodium punctatum forms great masses on the trees and sometimes a single plant may bear 300 or more flowers. These are of considerable size and, with the scapes, are yellowish green variegated with red brown, a most striking and beautiful plant. Oncidium luridum and its var. guttatum are very fine, having immense heavy leaves and long branching spikes of brown-red and yellow flowers. These spikes or panicles curve gracefully and are sometimes 10 feet long. Oncidium sphacelatum is an epiphytal orchid that has become terrestrial or sub- epiphytic in its habit, growing wild on decaying logs, the bases of trees, or even in the soil of pine woods. It has tall panicles of bright yellow and brown-green flowers. The last seven species are natives of Florida, and all of them are doing well in cultivation.
There is apparently no reason why anyone may not have a few of these strange and beautiful plants anywhere in Florida. In the northern half of the state, the hardy Florida species and others of similar character from northern Mexico, Japan, north India or the cooler parts of South America can be successfully cultivated, while in the warmer part of the state a large proportion of the tropical species can be grown. They do well on trees in hammocks, in artificial groves and even on isolated trees where they are not too much exposed. Nothing is more entrancing than the cultivation of these strange, often weirdly beautiful forms. If one once becomes interested in orchids he is sure to be a confirmed lover of them ever afterward. Chas. T. Simpson.
Cultivation of the various kinds of orchids.
At this point are brought together, in alphabetic order, the leading orchid genera for instruction as to methods of cultivation. The list is prefaced with remarks on orchids in general and their cultivation, even though they cover some of the ground already gone over in the article by Robert M. Grey, which was contributed to the Cyclopedia of American Horticulture. The orchids are so special in their requirements that another experience will be valuable.
Orchid-culture has ever been that of the few who are students of plant life and who can give time and care their plants. This statement has been exemplified many professional men who have used this means an alternative to their other cares and find it all-sufficing since so many species require special treatment and some are never understood. If evidence e needed, it is proved by the fact that so many fine collections are dispersed after the decease of their owners, and that decadence is the usual result with plants that thrived well before passing into other hands. There was also the added interest that when buying ported plants, the flowering of many rare and valuable kinds resulted, which at times paid a liberal interest on the original investment. It is safe to assume now that we shall secure relatively few more new species of value from the native wilds, these having been searched to such an extent that few are the expeditions now made up in search of them.
The greatest impetus in orchid-cultivation today is in the raising of plants by crossing and hybridization under conditions of cultivation, and the time is with us when we do not need to import either new species or plants of well-known forms. It is worthy of remark that the variation among orchids as we know them is such that no two plants are alike in the coloring or marking of the flowers. In the well-known Catlleya Trianae, or any other of the forms of the C. labiata group, each plant is different. Doubtless this is due to the fact that most orchids require insect agency for pollination. Usually each flower has a highly colored lip or labellum, to attract the insect, with radiating lines, or tracks leading to the nectar and, when this is secured, it is impossible for the agent to withdraw from the flower without taking toll in the shape of pollen which, of necessity, is deposited on the next individual visited.' In some orchids there are distinct keels on the lip, the track thus being emphasized and the bee compelled to take the narrow path that his mission shall be fulfilled.
It is often said that orchids need a well-marked period of rest. This is not always possible with specimens newly received from the wilds, as the flowering period has to be changed to accord with our winter or summer which in time governs their well-being. We will assume that the flowers have been pollinated by insect agency, and the seeds have matured. This maturation usually requires about a year. No one knows the number of seeds that will be contained in a healthy capsule. There must be tens of thousands, a very small proportion of which ever reach maturity when sown under glass; but here is apparently a reason for the time taken to ripen the capsule, that it may take place about the period for the plants to bloom again, which is presumably the most favorable or rainy season, and the seeds are distributed by the breeze to suitable media, and a proportion germinates and grows. We learn by sowing under glass that very few, even under the most careful treatment, ever live through the vicissitudes of initial stages, the tiny green globes or thalli having no true roots for months. It is perhaps a year after sowing the seeds before true roots are visible, but in the mean- tune, a hot drying day, if no gentle spraying of moisture is given, will blast all the hopes of many months' waiting: but we have the compensation of knowing that each plant we raise will be eminently fitted to survive under greenhouse conditions. The recent careful laboratory investigations have suggested rational methods of procedure in the growing of seedlings, and the subject will probably gradually pass out of the region of accident and doubt. (See page 2387.)
Variation that obtains among wild orchids is also present in various degrees among crosses and hybrids raised under cultivation. This was proved by the raising of over eighty plants of Cattteya Thayeriana, no two of which were alike, and some could not have been attributed to the same origin were it not for the connecting-links that rounded out the series.
In Europe, a great liking is shown for the coolhouse odontoglossums, especially since the raising of plants from seed has proved or illustrated the origin of many supposed species, the type flowers of which were sealed up for twenty-five years in Vienna in the herbarium of the late Professor Reichenbach who in his day, was the dean of the orchid botanists, and whose collection was but this year uncovered. Following is a clause in Reichenbach's will: "My herbarium and my botanical library, my instruments, collection of seeds, etc., accrue to the Imperial Hof Museum in Vienna, under the condition that the preserved orchids and drawings of orchids shall not be exhibited before twenty-five years from the date of my death have elapsed. Until this time my collection shall be preserved in sealed cases. In the event of the Vienna Institution declining to observe these conditions, the collection falls under the same conditions to the Botanical Garden at Upsala. Should the last-mentioned institution decline the legacy, then to the Grayean Herbarium in Harvard University, Cambridge, Mass. If declined by that institution, then to the Jardin des Plantes, at Paris, but always under the same conditions, viz., of being sealed up for twenty-five years, in order that the inevitable destruction of the costly collection, resulting from the present craze for orchids, may be avoided. See Bailey, "Annals of Horticulture," 1889, with portrait, of Reichenbach, from "Gardeners' Chronicle." In the meantime, after the first lamentations, and the gathering of the available living types, cultivators began work with such authentic material as they had until now we have plants with three to four genera in their parentage, and the end is not yet. It will readily be understood that the recording and taking care of the nomenclature of these results as they occur week by week, is no simple matter, but it is being undertaken in such a way that for the present we know the origin of the many plants that have been raised. There is no other record in plant hybridization to compare with that of the orchids. In most cases, drawings have been made of the originals for filing in the archives. The Mendelian theory will surely find much material in the work of the orchid-cultivators, because of their painstaking in the matter of pedigree. It was early decreed that a plant without a pedigree could not be considered for recognition with a name. This seemed hard at times, because of special merit, but the cultivator had to be content with the result rather than with the honor. It is a curious circumstance that in the raising of orchids from seeds, many appear where they were not sown and in the most unexpected places. These are later placeable where they belong if there are other forms with which to connect them, but failing this there is no admitted reason for giving a name.
In past years, large prices were paid for forms of orchids that were unique, as for albinos, specially marked, or highly colored variations, all being imported forms. It was thought that these could be reproduced from seeds; this has not been true in most cases, even albinos having reverted to the normal and in most cases very poor forms. It is now a recognized principle that none but the very best varieties should be used as parents, and from these there are always a number of degenerates.
Orchid-hybridization is not prosecuted in America to the extent that it was at one time. It requires years to secure results that are obtained at far less cost in Europe, where the plants are more easily obtainable. We may mention a case in which nineteen years was required to flower a plant, the only one that survived from a certain cross, and when it bloomed it was of no value although true to its parents, one of which was of poor constitution.
General cultural requirements.
Most tropical orchids of cultivation are epiphytal, very few growing on the soil, and the requisite conditions are largely a matter of atmosphere,—not necessarily temperature. Heat is necessary, but only to be taken seriously in winter when it is generated artificially, sometimes from superheated pipes, which is always detrimental to the well-being of the plants. It is better to have a number of pipes heated to a moderate degree. In summer the heat is not a factor except with the cool Andean plants like the odontoglossums. If plenty of ventilation is given from the time frosts cease at night, one cannot imitate easily the night atmosphere outdoors, and the more the plants get of it when genial, the better they thrive.
Another factor under glass is shade from the sun. This must be governed by the amount of direct light admitted. It must be understood that a house running north and south will not get so much heat from the sun's rays as one built east and west. In a house having full exposure to the sun in winter, orchids will need shading to some extent most of the winter, while one running north and south will not have to be shaded from the month of October until March. The plants are injured by the loss of green in the foliage due to exposure. Part of this will return when shade is given, but some of the older leaves will turn yellow and drop off. It is the medium course that conserves vitality, while ripening the growths perfectly, that the cultivator needs to bring about. The successful grower gives intensive study to each individual plant. We have had the experience of miltonias that thrived perfectly at the end partition of one structure, but never prospered when they were removed to other similar conditions. It was a question of exposure. So it is that cultivators often place a plant in a particular position in a house, seemingly the purest empiricism, but a practice not to be despised by those who want to succeed. It is not surprising that plants collected from the odd corners of the tropics, placed together in a small house where the temperature is to be maintained largely by artificial heat, require careful and individual study. With many difficult orchids, one cannot imitate the atmosphere of the Andes when the dog-days come, or when zero temperatures obtain outdoors and the wholesome atmosphere disappears by the exhaustion from superheated pipes.
Orchid-culture in America will be largely confined to a few genera, the "cool" kinds will rarely succeed, but those from Mexico to Brazil and most of the East Indian and Philippine kinds can be made to thrive better here than in Europe.
A number of American terrestrial orchids are amenable to cultivation. Cypripediums lend themselves kindly; and most of the others, as the calopogons, spiranthes, pogonias and habenarias, are plants essentially of the swamps or woods where moisture is secure all summer, but are not easily tamed in the usual way as are other plants, and yet their essential conditions may be met by the careful and thoughtful gardener.
The main cultural groups.
The orchid family is usually classified by growers into at least three divisions, for providing suitable temperatures and other conditions, especially atmospheric, although a closer analysis would make at least four cultural groups.
1. The warmest division should be kept at a minimum of 65° in winter, to take care of the vandas, aerides, saccolabiums, phalaenopsis, angraecum, anoectochilus, habenaria, a few of the strictly tropical dendrobes and other less known genera. Most of these may be termed extra- (or supra-) epiphytal for the reason that they secure most of their needed moisture through their large aerial roots, the material that they are planted in being secondary in importance as a source of nourishment. There are many cypripedes that need this warm treatment, such as the Malayan, Bornean and some of the East Indian species, for they speedily resent being chilled. The higher temperature makes the cultural details in winter more difficult to regulate since moisture must be kept up to counteract the dry heat from the pipes; therefore it is always best to have a number of pipes moderately warm rather than a few superheated. Insect pests are also more persistent under superheated conditions. Thrips and red-spider are harder to fight, and must be kept down by frequent light sprayings with approved insecticides containing nicotine, applied with an atomizer once a week in case of an invasion. Troughs on the heating-pipes for the evaporation of water are essential, and sometimes, in large structures, open tanks are used under the stages on which the plants stand filled with water which is heated by coils. Too much emphasis cannot be placed on the keeping of a proper atmosphere as well as heat for these tropical plants. This can be brought about by proper ventilation and shading from the hot sun, to prevent the escape of the atmosphere when it has been secured. Most of the foregoing orchids are natives of the tropical jungles where shade is ever present, and exposure suddenly after a few dull weeks to the hot rays of the sun under glass in early spring will do harm.
2. The temperate division is the home of by far the largest number of the cultivated orchids. A night heat of 50° in winter as a minimum on extreme cold nights will be better for the plants than a higher temperature. It is well known that, after a period of severe cold, many of the older leaves of cattleyas turn yellow and fall off, a sign of the stress to which they have been subjected. In moderate weather, 55° will be better, especially if plants are in bloom. In addition to the cattleyas, the laelias, cymbidiums, sobralias, oncidiums, stanhopeas, epidendrums, brassias, miltonias, catasetum, phaius, the Mexican odontoglots, and East Indian dendrobes, and many cypripedes, will thrive best in the temperate house. If but one house or division is to be devoted to orchids, this should be an intermediate one for the reason that, with the exception of the purely tropical species and the coolest Andean, the greatest number can be cultivated therein by the careful utilization of the various parts of the house for individuals that need the warmer or cooler end or a little more shade, conditions that are soon discovered by the observant cultivator. The admission of fresh air when weather permits is of the utmost importance. In summer the house should have free air day and night from the first of May until late September. It is the greatest factor in building up the plants after the exhaustion of flowering. At this time, watering should always be performed in the late afternoon; and if watering is not necessary, spray the plants overhead after each very hot day. In winter, water is best given in the morning that the surplus will dry off before night.
3. A coolhouse is necessary for the Andean odontoglots, cochliodas and their now numerous hybrids, the sophronitis, disas, masdevallias, Coelogyne cristata, Epidendrum vitellinum, lycastes, and a few other plants. These are among the most charming of all orchids, the odontoglots especially. Difficult as the odontoglots are to manage, much success has been attained by care and suitable structures, preferably with a north slope with the shade of some other building to the south. Roller shades on the coolhouse should be kept about 12 inches above the glass roof to admit of a free circulation of air beneath in hot weather, with ventilators at the top and bottom near the pipes. Cool orchids require to be kept moist all the time. There is no very marked period of rest, as they are subject to heavy night dews where they grow; but in the dull winter months, all the sunlight must be admitted, as most of the active growth is made in winter and early spring. These plants are a real test of the skill of the grower. A few cool summers build up the plants so they flower well and it has been noticed that the best results are obtained in the cooler parts of the country, or near the seashore.
Further suggestions; propagation.
Many genera in cultivation are seldom seen in collections here, but a knowledge of their native habitat, and especially the elevations at which they grow, must be the clue to their needs in cultivation, together with a study of their root-system. The roots that are white, are aerial, and those that have root-hairs are terrestrial, and being of the earth will best be treated as pot- plants.
Many species are easy of propagation by division, and it is often advisable to divide plants rather than grow them on into large specimens. The plants should be kept in reasonable size. Propagation by means of seeds is a slow process, and in many cases one cannot be sure what will come true from seed. Even from well- marked types there is always the possibility of reversion. Especially is this the case with albino forms, so many of which occur among imported specimens.
Cultivation of leading genera of orchids.
Acanthophippium. For culture, see Acanthophippium.
Acineta. For culture, see Acineta.
Ada. A small genus of few species with bright orange-colored flowers that add color to the coolhouse among the odontoglots, and require similar treatment.
Aerides. True epiphytes that revel in a moist atmosphere in a warmhouse with a winter minimum of 65°. Very little potting material in desirable, just enough to anchor the plants in the pots. The roots made from the stems as the plants grow seem to gather the needed nourishment, and care must be taken not to injure these or check them, as they arc very active, even in winter. Some of the species are very fragrant, all are beautiful and last a long time in bloom. A surfacing of moss should be added to a thin layer of osmundine, and the drainage made up of large pieces of charcoal and crocks. Basket culture is often adopted, but it is hard to re-basket without injuring the roots, but the old material may be removed, the roots washed and new added each year until new baskets ore necessary by reason of decay.
Aganisia. Warmhouse plants, needing little material about the roots, and to be suspended near the roof glass with a maximum of light but no direct sun in summer.
Angraecum. Culture as for Aerides.
Anguloa. Culture as for Lycaste.
Anoectochilus. Terrestrial tropical orchids with creeping root- stems, foliage beautifully marked, the Malaccan name being "written flower" owing to the marking resembling hieroglyphs, done in many colors. These plants are best grown in the warmest part of the structure, in a small frame or under bell-glasses to keep the leaves unspotted and ensure uniform heat and moisture, but some air must be given to guard against condensed moisture and consequent drip. Difficult to import and not often seen in collections.
Ansellia. A tropical African genus of a few species growing on trees, where there is a climate of abundant moisture during the growing period, with a dry season of about half the year. Culture in the warmhouse, witholding water to ripen the growths well after they are completed.
Arachnanthe. Culture as for Aerides.
Arpophyllum. A temperate house genus seldom seen in cultivation, coming from high altitudes in Mexico and Guatemala, best grown in baskets, in shade and plenty of moisture. Culture same as for Lycaste.
Aspasia. Once considered as odontoglossums. There are about eight known species, seldom cultivated, requiring treatment as for odontoglots.
Batemannia. Plants that are never at rest, needing a moist tropical atmosphere, with no appreciable resting as water is needed all the time. Very little material is needed at the roots, and this kept in a sweet healthy condition by adding new material and the removal of old portions. Red-spider must be kept away by frequent washing of the foliage.
Bifrenaria. Brazilian plants requiring treatment same as cattleyas from that region, and a trifle warmer position than for those from Colombia.
Bletia and Bletilla. Cool terrestrial plants, but not hardy. Can be grown in an ordinary greenhouse and kept dry in winter when at rest, repotting in fresh material when growth begins in spring.
Bollea. Culture as for Batemannia.
Brassavola. Best known by reason of B. Digbyana, which is so much used by the hybridist to put the fringed lip on cattleyas and laelias, with which it can be combined readily. Of culture the same as for cattleyas, slow to increase by division, but otherwise easy of culture.
Brassia. These are seldom seen in modern collections, but were old-time favorites, growing and flowering freely in an ordinary structure with no special care, and may well be associated with the warm oncidiums as to potting and subsequent routine.
Broughtonia. The only species known in cultivation here, B. sanguinea, is hard to cultivate for any long period. It is best attempted on a portion of osmunda rhizome, with a little moss at the roots, hung near the gloss in the warmhouse.
Bulbophyllum. Among these are the giant* among orchids. Some species attain huge size, require tropical treatment in a steaming atmosphere during growth and the flowers when produced are remarkable, though very seldom seen except in botanic gardens. Some species are small and require to be grown on blocks of wood; increased by division.
Calanthe. Deciduous bulbs that need rest after the flowers are cut in midwinter, until there are signs of growth in spring, then shaken out to be potted in turfy loam, a little well-decayed manure, in pots or pans with good drainage. The warmest position or shelf with shade will best suit calanthes. It might be said they will enjoy a little fire heat every day in the year, with proper shade and plenty of moisture. The long flower-scapes begin to develop in late summer, and when these appear liquid nourishment must be given frequently to grow large bulbs. The flower-scapes are long, last a long time in perfection when cut, and as the flowers open, cooler and drier treatment may be given. Increase is readily made by means of the old bulbs that will often grow again, and these often double in number each year. A valuable florists' orchid when its culture is understood, and profitable to grow.
Calopogon. For culture, see Calopogon.
Camarotis. Culture as for Aerides and Vanda.
Catasetum. Curious and beautiful orchids from Central America, that often have the two sexes in different individual plants, a fact that was long a puzzle to botanists, and the peculiar structure of the Sowers makes the plants very interesting. The culture is not easy in gardens; plants usually dwindle after a few years, but plenty of heat and light when in growth, with a long resting-period between, is necessary, and growth is best when the plants are suspended from the roof.
Cattleya. The most popular and best known of the orchids grown for cut-flowers, with few exceptions. Best grown in the intermediate house. For culture, see Cattleya.
Chysis. Culture as for Vanda.
Cirrhopetalum. For culture, see Cirrhopetalum.
Cleisostoma. Culture as for Aerides.
Cochlioda. A genus much prized by hybridizers of late for the color it imparts to the odontoglossums, the hybrids of which are now known as Odontioda and form a pretty rose-colored series of cool orchids, very popular where they thrive. Treatment same as for odontoglossums.
Coelia. Culture as for Epidendrum.
Coelogyne. Terrestrial orchids, both temperate, as C. cristate, and tropical, as C. Massangeana and C. pandurata. Species like the last two need basket culture suspended, as their flower-spikes are dependent. The well-known C. cristata will do well in a coolhouse when at rest before flowering, Boil containing a portion of earth, and liquid manure during growth is necessary to produce strong flowering growth, increased by division directly after flowering period.
Colax. Culture as for Lycaste and Zygopetalum, in an intermediate house.
Comparettia. Culture as for Broughtonia, but in an intermediate house.
Coryanthes. Culture as for Stanhopea.
Cycnoches. Curious Central American plants, often called the "swan's-neck orchid," requiring treatment identical with that of dendrobium, and well-marked resting-period after growth is completed.
Cymbidium, Decorative evergreen tall-growing plants that have many flowers of long duration. All are from the East Indies, but do well in an intermediate and even a cool house in winter. They also do well when planted out among rockwork in large structures, and the hybridist has added very many fine plants that go to make up the collection in gardens. A soil with loam added and manure- water added frequently when the plants are growing or rootbound will induce strong growth. The plants are impatient of disturbance at the roots, but if carefully done they may be increased by division. Seeds germinate freely. For further cultivation see Cymbidium.
Cynorchis. Terrestrial plants from Madagascar and Natal. Culture same as for Bletia, repotting in fresh material in spring.
Cyperorchis. Culture as for Cymbidium, to which genus they are sometimes referred botanically.
Cypripedium. Terrestrial orchids, although sometimes growing on rocks with little humus about the roots, including tropical or warmhouse plants {now referred to Paphiopedilum), these being often with mottled foliage; intermediate house plants as Paphiopedilum insigne and its many hybrids, and the hardy species, always deciduous and widely distributed. Cypripediums are herbaceous, having no pseudobulbs, and should never lack for moisture or be overpotted. Propagation by division or seeds, which germinate freely. Albino forms have been reproduced by seeds, to a large degree true to the parent plant; also specially fine varieties.
Cyrtopodium, Culture same as for Cycnoches, repotting in spring; carefully shade the young foliage until mature. Flowers are produced with the commencement of young growth in spring. Avoid spraying over young growths, as water lodging often induces decay unless the house is well ventilated and the day bright.
Dendrobium. For culture, see Dendrobium.
Diacrium. Culture as for Epidendrum and Cattleya.
Disa grandiflora. An orchid from Table Mountain, is now protected by the state, owing to its scarcity due to collectors, is a very beautiful plant when in bloom, but it is doubtful whether it has ever been cultivated here with success, though not difficult to handle in European gardens, where it is easily raised from seeds and by division. It is strictly terrestrial, but seems unable to bear heat. There are several other species and many hybrids from these, but none seems amenable here.
Epidendrum. A genus of very much varied plants, some being stem-rooting and without bulbs, and these require all the sun to flower freely; others have pseudobulbs, arc easy of culture and do well in the intermediate house, with treatment same as for cattleya. For further culture, see Epidendrum.
Eriopsis. Culture as for Lycaste, in shallow baskets suspended in an intermediate or cattleya house. Repot when growth commences, with great care, as the plants are impatient of root-disturbance. E. rutidobulbon is the best known species, but it is very rare even in its native Antioquia.
Eulophia. Culture as for Calanthe.
Galeandra. Culture as for Calanthe.
Gomexa. Culture same as for Broughtonia. A Brazilian genus, species of which are rarely seen in cultivation, being largely of interest in a botanical way.
Gongora. Requires to be grown in baskets suspended, as the flower-spikes are produced from the base of the plant downward. No obstruction by way of drainage should be allowed to hinder these. An intermediate treatment, with less water when resting will suit the plants. They are seldom seen, as the flowers hare no bright coloring to attract, though some are very fragrant.
Grammangis. For culture, see Grammangis.
Grammatophyllum. For culture, see Grammatophyllum.
Habenaria. Both tropical and temperate species are included. The plants are always deciduous and the warm species need resting until new growth commences, then careful repotting in new material. A warm shady corner suits their needs best. The hardy species are found in both the Old World and New, growing in moist rich soil with partial shade, but sometimes in full sun in marshy land.
Haemaria. For culture, see Haemaria.
Hartwegia. Rarely seen. Culture as for Gomesa.
Houlettia. Culture same as for Stanhopea, in intermediate house, kept rather dry in winter, using baskets.
Huntleya. Culture as for Batemannia.
lonopsis. For culture, sec lonopsis.
Isotria. Culture as for Pogonia.
Lacaena. For culture, see Lacaena.
Laelia. For culture, see Laelia.
Laeliocattleya. For culture, see Cattleya and Laelia.
Leptotes. Culture as for Laelia.
Limatodes. For culture, see Limatodes.
Liparis. For culture, see Liparis.
Lissochilus, A tropical African group, requiring soil similar to phaius, made up of part good loam, with a little old manure, sand, and plenty of drainage. In Africa the plants arc sub-aquatic, and have been cultivated with water-lilies. This is not generally practised, however. The flower-spikes sometimes attain 12 feet in height in L. giganteus. The warmest house is necessary, with frequent application} of liquid manure during growth with somewhat drier treatment in winter until new growth begins. Shade in summer is necessary as the foliage is thin when new.
Listrostachys. Culture same as for Angraecum or Phalaenopsis, in very shallow pans as the plants are small.
Luisia, For culture, see Luisia.
Lycaste. Semi-terrestrial orchids requiring intermediate treatment with shade from direct sunlight at all times as the foliage is thin and easily injured. L. Skinncri is often grown in baskets suspended, but should be kept moist at all times as Sowers are produced at various seasons, and growth is often being made during the whole year. A portion of loam in the soil, or the heavier grade of osmundine is best suited to the roots of orchids of this nature. Propagation by division.
Macodes. Culture as for Anoectochilus.
Masdevallia,. Of all Andean orchids these do the best in an ordinary coolhouse when shaded from sun, and watered frequently, for, having no pseudobulbs, there is no reservoir to draw upon. The colors of most masdevallias are wonderful, and the plants easy of culture in the usual orchid material. Increase is readily made by division of the stems just after flowering, being careful to save the roots intact. For further cultivation, see Masdevallia.
Maxillaria. Once a very well-known genus of free-flowering orchids of easy culture, some species being fragrant, but of late, owing to the small flowers and dull coloring, the plants have disappeared from collections with the possible exception of M. Sanderiana, which is an exception as to coloring, it being attractive and the flowers large. Treatment as for Lycaste, and propagation by division.
Mesospinidium. Culture as for Cochlioda, to which it is closely allied.
Microstylis. For culture, see Microstylis.
Miltonia. These were long known as odontoglossums, and M. vexillaria is one of the prized orchids today. It is a little particular as to position in the house, needing plenty of sun during the winter, which is the period of growth. After flowering, in May or June, there is a short time of rest, when the plants ore much weakened and need careful nursing with shade to enable them to recuperate and make strong growth again. M. Roezlii is very similar, but is a warmhouse plant requiring 10° more heat, and flowers in winter. These are the two best known species, but, with the exception of M. Roezlii, all need the intermediate house. Propagation is by division when growth is starting, at potting time.
Mormodes. For culture, see Mormodes.
Mysticidium. Culture as for Angraecum.
Odontoglossum. A very popular genus in Europe, but difficult to grow well here owing to the extremes of temperature. Natives of the Andes, where the temperature does not vary 10° winter or summer. Some success has been attained here, especially during cool summers. For culture, see Odontoglossum.
Oncidium. There are a large number of species, ranging from the alpine Andean small-growing ones to large tropical plants. No genus of orchids presents such wide variation and study. Their culture is easy when the needs of the individuals are studied, and these arc governed by the elevation at which the plants are found growing and imitating as well as can be the temperatures. Some of the cool species need moisture all the time, while the Mexican and Central American ones do best with a denned period of rest, meaning less moisture and heat, generally in the winter, sometimes before flowering and often after. The intermediate house will suit all except the cool ones. The flower-spikes are often very long, as in O. macranthum, and need careful training to keep away from the glass. O. Rogersii is perhaps the best known and is a popular florists winter-flowering orchid imported annually in quantity. The usual potting material is suitable, but oncidiums seem to do best when restricted as to root-room.
Ophrys. Culture as for Habenaria.
Palumbina. Closely allied to oncidium, and sometimes included. Culture as for the intermediate house oncidiums.
Paphinia. For culture, see Paphinia.
Paphiopedalum. For culture, see Paphiopedalum and Cypripedium.
Peristeria. A tropical orchid requiring much the same treatment as calanthe when growing, but the peristeria does not need such a marked period of rest, as it is evergreen. It is terrestrial, requiring a loam mixed with old manure, and liberial supplies of moisture. If black-spot disease appears, it must be cut out at once and the cavity filled with lime and sulfur. This disease seems to be common. The tall spikes of sweet-scented flowers, the center of which resembles a dove, are much admired and last long in perfection.
Pescatoria. Culture as for Zygopetalum.
Phaius. Eastern tropical plants of great beauty, one of which has become naturalized in the West Indies. Terrestrial in habit, needing a soil composed largely of loam rich with humus, and liberal feeding when in full growth. Propagated by division, after flowering.
Phalaenopsis. Tropical epiphytes needing the warmest temperature admitted in orchid-culture, which is a minimum of 65° in winter and this in the coldest weather, and an atmosphere never allowed to become arid or stagnant. At some seasons drip from above easily proves fatal. Very little material is needed at the roots, as they love to escape the receptacles when doing well and hang pendent. Osmundine is the most suitable material to use as it is lasting, but where sphagnum will live and keep green it is well to use it as an index to the need of moisture. Many growers never spray phalaenopsis overhead, water in the center of the plants often causing decay, but in very hot weather this will evaporate by the addition of air. Having no pseudobulbs, but a pair or more of large leaves to support, the plants must never lack moisture. The flowering period is mostly in winter or early spring and the beautiful sprays of bloom are now a large item among growers for market since the plants can be so readily obtained from the Philippines. There is a tradition that phalaenopsis do best near the coast. Certain it is, that California growers are having great success with them.
Pholidota, For culture, see Pholidota.
Phragmipedilum. For culture, see Phragmipedilum.
Physurus, From Colombia, but with foliage similar to the anoectochilus from the Malay Archipelago. Physurus grows at an elevation of 5,000 to 6000 feet and will thus be best treated in the same house with the odontoglots. One species occurs in Peru.
Platyclinis. Warmhouse plants, all of which have fragrant flowers, and are easy of culture. The best known is P. glumacea, but P. filiformis is sometimes seen. Easily grown in osmundine and propagated by division.
Pleione. A pretty genus of East Indian plants known there as the crocus. Flowers mostly pink, and produced after the foliage has died down. Best grown in shallow soil in pans, with treatment as for calanthe.
Pleurothallis. Small-growing plants of great interest botanically but many have flowers that require the aid of a microscope to see their beauty. Best grown in the cattleya house in shallow pans suspended near the glass. They need moisture at all times out very little material at the roots. In summer the plants may be placed with the masdevallias, at the warm end of the odontoglossum house.
Pogonia. Hardy orchids found in wet soil with very showy flowers, but difficult to transplant unless plenty of earth is taken with the roots.
Polystachya. A tropical African genus, rare in cultivation.
Promenaea. Culture as for Zygopetalum.
Renanthera. Culture as for Vanilla.
Restrepia, For culture, see Restrepia.
Rhynchostylis. Culture as for Saccolabium.
Rodriguezia. For culture, see Rodriguezia.
Saccolabium. Culture as for Aerides. See also under Saccolabium.
Sarcanthus. For culture, see Sarcanthus.
Sarcopodium. A genus separated from Dendrobium and Bulbophyllum, and requiring treatment similar to that of Dendrobium.
Scaphosepalum. For culture, see Scaphosepalum.
Schomburgkia. Culture same as cattleya. but requires to be well ripened by exposure to more sun, especially in winter, to induce flowering. The plants are seldom seen, as they are large, and the flowers inconspicuous by comparison with other orchids, borne on stems sometimes several feet long.
Scuticaria. For culture, see Scuticaria.
Serapias. For culture, see Serapias.
Sobralia. A group of reed-like plants, flowering at the end of new shoots, several large cattleya-like flowers coming in succession, but, these being short-lived, are of no value commercially, but are interesting plants in a collection. Specimens may be grown to a large size and the plants do not deteriorate. Many hybrids have been raised, but are seldom seen in gardens. Propagation by division usually, and a soil as minted for coelogyne.
Sophronitis. A brilliant-colored little orchid, an alpine plant. Easy of culture in shallow pans suspended near the roof. S. grandiflora is the best known, and has been much prized for imparting its color to the larger cattleyas and laelias. At least one hybrid has been raised here, and many more in Europe and Britain. The color is usually equally brilliant in secondary crosses. Does best in the cattleya house and should never become dry at the roots or the plants will suffer.
Spathoglottis. For culture, see Spathoglottis.
Spiranthes. Hardy native orchids popularly known as "ladies' tresses." Easily transplanted, but seem to flower biennially, late in summer and early autumn.
Stanhopea. Treatment similar to gongora with similar pendent flower-spikes through the bottom of basket. Flowers very striking in color and odor, but do not last long.
Stenorynchus. Tropical plants allied to spiranthes, with variegated leaves and colored flower-stems. Treatment same as for Paphiopedilum.
Thunia. Tall-growing bamboo-like stems with clusters of flowers at the top. Very attractive but not often seen owing to the attacks of red-spider on the thin foliage. After flowering, the plants need resting, being kept dry but in a warm house, until growth starts again. Propagation is by cutting the stems in pieces with several joints, laying on damp moss in a propagating-case in strong heat until roots are visible, then potting and treatment as with older plants. Loam should be added and weak liquid manure-water when rapid growth is produced.
Trichocentrum. For culture, see Trichocentrum.
Trichosma. Only one species seems to be in cultivation, T. suavis, a very pretty fragrant-flowered orchid, needing intermediate house treatment, with culture same as for cypripediums, repotting to be done in winter after flowering season has past.
Tricopilia, Beautiful and fragrant orchids, free-flowering, needing same culture as lycaste.
Vanda. Culture as for Aerides. See also under Vanda.
Vandopsis. Culture as for Vanda.
Vanilla. Tropical epiphytes producing a valuable bean-like capsule and the only orchids known that have a commercial value apart from the flowers. They are true epiphytes, requiring support such as a wall at the end of an orchid house where moisture is assured for the creeping roots. Pollination must be done by hand to be sure of pods being formed. The culture of vanilla is carried on on a large scale in the tropics, but it is impracticable under glass. Easily propagated by cutting up the rooted stems into pieces.
Warrea. Culture as for Phaius.
Warscewiczella. Culture as for Zygopetalum.
Zygopetalum. Very decorative winter-flowering plants, Z. Mackayi being of easy culture, and perhaps the only species well known. It is very free-flowering, fragrant, will seed freely and produce plants true even though hybridized by other pollen, even unto the fourth generation. It is one of the oldest known orchids, requiring soil similar to phaius and an intermediate treatment.
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