ORCHID VARIETIES

People generally think of orchids in the context of lush, tropical vegetation, but many species are found not only in sub-tropical regions, but also in cooler parts of the world, even beyond the Arctic Circle. The orchid family (Orchidaceae) is one of the largest in the whole plant kingdom. Species differ not only in the shape of the body, but also in their ways of life.

Some species lack chlorophyll and cannot, therefore, photosynthesize organic compounds. Instead, they live in symbiotic association with the mycelium of a fungus. This phenomenon is called mycorrhiza. It is an important factor in the life of all orchids, particularly in the early stages of development – during germination. It has probably something to do with the transfer of enzymes. Orchid seeds contain hardly any reserve stores of food. The filaments of the mycelium penetrate the root cells of the orchid and multiply there. The plant cells feed on the contents of the filaments. Adult orchids with a sufficiently large leaf area to produce their own food by photosynthesis soon cease to depend on the fungus. Orchids that lack chlorophyll, however, are dependent on the symbiotic association with the fungus throughout their lives.

Some species of orchids are epiphytic, that is, they grow on other plants without obtaining any benefits from them or doing them any harm. Others are terrestrial, that is, they grow on the ground. Many have rhizomes or tubers; others have no roots of any sort. Stems may be erect or drooping, jointed or without joints, covered with leaves or leafless.

The most ornamental feature of orchids is the flower. The flowers always have only one plane of symmetry and an inferior ovary that develops into a capsule. The showy and often fragrant flowers attract insects but they are deceptive blossoms, for they do not produce nectar.

Paphiopedilum orchids are distributed throughout the tropical and sub-tropical regions of southeast Asia, and include some 50-60 species, plus numerous cultivars. Members of this genus have large, usually solitary flowers. The slipper-shaped lip is their most striking feature. The scape grows from a rosette. It flowers from autumn until spring. The flowers are up to 10 cm (4 in) across.

Paphiopedilum concolor

This species is native to Vietnam, Thailand and Burma.

The leaf rosette is composed of dark green leaves, marbled greygreen above and reddish-brown beneath. The scape, usually with a single flower, is up to 100 cm (39 in) tall and thickly covered with reddish hairs. The flowers are 6-8 cm across and coloured ochre-yellow spotted with violet. They are very long-lasting, remaining on the plant for 6-10 weeks, or for a slightly shorter time when cut and put in a vase.

P. concolor grows well in a mixture of osmunda fibre, fresh sphagnum moss, crushed bark and dried oak leaves. Growers often prepare their own mixtures, based on experience. Whatever medium you choose it is important that it is free-draining. Water regularly, as paphiopedilums have no storage organs – pseudobulbs – and so no period of rest; the growing medium must never become dry. The temperature of the environment depends on the species. In general, paphiopedilums with marbled leaves require higher temperatures – a minimum of 17°C (63° F).

Paphiopedilum fairrieanum

This species has, perhaps, the most beautiful flowers of the whole genus. It was brought to Europe from Bhutan in 1857, but it died as a result of improper cultivation by the first growers. It was not cultivated again for 50 years.

It is a lime-loving species and so lime should be added to the substrate. Roots and shoots begin growing from about April, when it requires regular misting to increase humidity. Provide good ventilation and light shade from spring onwards. Increase day and night ventilation in summer. The autumn and winter temperature should be I5°-18°C (59°-64°F) during the day and 15°C (59°F) at night. Once the flowers have died, reduce watering.

Paphiopedilum callosum

This species , native to Thailand, is distinguished by marbled leaves and a scape, 25-30 cm (10-12 inch) high, which bears one or two flowers 8-12 cm (3-5 in) across. It is a thermo philous orchid. It requires a temperature of at least 18°-22°C (64°-72°F); ideally 22°-26°C (72°-79°F).

Oncidium papilio

Butterfly Orchid is distributed in Venezuela, Peru, Ecuador, Colombia and Trinidad. The genus Oncidium is one of the largest genera of epiphytic orchids. The shape and colour of the flowers make them seem like some exotic butterfly (the Latin papilio means butterfly). Although in some Oncidiums the pseu-dobulbs are reduced or absent, those of this species are well developed. A leaf, 15-18 cm (6-7 in) long with faint reddish blotches, grows from each one. The thin, firm scapes are terminated by a single flower about 8 cm (3 in) across, conspicuous by the three erect, linear perianth segments up to 12 cm (4 ¾ in) in length. This is a thermophilous species and the conditions for growing are the same as for Cattleyas .

Angraecum sesquipedale

This epiphyte belongs to a genus of about 50 species that grow in Africa and Madagascar. The blue-green leaves are fleshy and covered with a waxy coat. The scanty inflorescences are composed of two to four white flowers, 12-15 cm (4 ¾-6 in) across.

This orchid requires very warm conditions. The optimum temperature in spring and summer is 20°-26°C (68°-79°F), in winter 17°-22°C (63°-72°F). Mist regularly in summer. The growing medium should be a mixture of fern roots, fresh sphagnum moss, beech leaves and charcoal.

Angraecum

The scapes are up to 1 m (39 in) long, the leaves are long eichlerianum and elliptic and the short-stalked flowers are either solitary or in pairs. The perianth segments are pale green. The lip is shellshaped, broad, and coloured white with a greenish-yellow throat. The spur is about 4.5 cm (1 ¾ in) long and geniculate. Cultivate in the same way as A. sesquipedale . It grows well in a hanging basket, perforated pot or even on a cork tile to which some kind of organic material is affixed.

Miltonia – hybr.

Pansy Orchid is a tropical epiphyte native to Brazil and Colombia. It has short pseudobulbs, usually bearing two leaves, and upright racemes of few flowers. These are a veritable kaleidoscope of colour. The perianth segments are typically all flat and practically identical, reminiscent of pansies. Miltonias are very ornamental indoor plants, but they are not suitable for cutting because the flowers last only a few hours.

To provide the right conditions for growth, it is necessary to know the place of origin of the species, for Brazilian and Colombian species have different requirements. The first group in eludes M. anceps and M. Candida, which require warm, shaded conditions and liberal watering in summer; during the rest period, water only to keep the soil moist. The second group, which includes Miltoniopsis vexillaria and M. phalaenopsis, requires cooler conditions; these orchids are grown at a temperature of about 18°C (64° F). Hybrids of both groups are grown in the same way.

Cattleya – hybr.

Cattleya is a South American genus with 40-50 species, hundreds of varieties, and countless hybrids, the result of both spontaneous and selective cross-breeding. They are divided into two groups. The first includes thermophilous, bifoliate species, that is, those with two leaves growing from the pseudobulbs. They have smaller, more numerous flowers. They flower without a rest period after the pseudobulbs have formed. C. intermedia is an example of this group. The second, unifoliate group includes Cattleyas that require a rest period between the time that the pseudobulbs are fully developed and the formation of the flowers. C. labiata is an example of this group. The rare cultivar ‘Golden Jay’ is noteworthy for the unusual colour combination of the perianth segments and the lip.

Repot in the third or fourth year between March and June, when new roots and shoots start to grow. Remove old pseudo-bulbs that are without leaves and roots. Leave at least three healthy pseudobulbs on the plant. ‘Madame Marons’ x Brassocattleya.

Because Brassavola and Cattleya are generically close, crossbreeding is very simple and the result is the intergeneric hybrid x Brassocattleya. It is readily identified by the fringe along the entire perimeter of the lip. Cattleya, of course, can also be cross-bred with other genera, for example with Laelia; the hybrid obtained from this crossing is called x Laeliocattleya. These cultivars come in a wide range of colours and their cultivation is the same as that of thermophilous Cattleyas. The cultivar illustrated has deep pinkish-violet flowers, the inside of the lip is yellow.

Cattleya intermedia

This orchid is very popular with growers because of its large, magnificent flowers and their longevity. It is native to Brazil. The large, narrow pseudobulbs produce two leaves. The inflorescence is composed of two to eight flowers; these are borne practically without a break from spring until autumn. The cultivar ‘Alba’ differs from the type species by having white blossoms.

Conditions for growing both the white-flowered cultivar and the type species are the same. The spring temperature should be 20°-27°C (68°-81°F). Shade the plants from too much sun. Good ventilation is essential. In summer the room should be aired frequently, even at night, and the temperature should not fall below 30° C (86° F). The winter temperature should be 18°-23° C (64°-73°F) during the day and 13°-16°C (55°-61°F) at night. Water liberally and mist frequently; do not allow the plant to become too dry during the growing season. Maintain high humidity – at least 50 per cent – even in winter, and never water the plant with hard water.

Cymbidiums are readily grown indoors. The genus Cym-bidium includes some 50 species distributed from Madagascar through India to Japan and south to Australia. They usually have very short stems, thickly covered with leathery leaves and flowers arranged in spikes. They are good for cutting; the flow ers are very long-lasting. Too vigorous growth may be a problem. Plants can reach a height of 1 m (39 in) and produce leaves up to 70 cm (28 in) long. Horticulturists, therefore, try to develop low-growing forms.

They are mostly terrestrial orchids and so grow well in pots. They even have no special compost requirements. Many cym-bidiums like cool conditions. Maintain a temperature of 10°-16°C (50°-61°F) during the rest period after flowering.

Phalaenopsis amboinensis

This epiphyte is one of 40-50 species of Phalaenopsis, distributed throughout India, Malaysia, the Philippines, New Guinea and northern Australia. They do not have pseudobulbs and the stem is greatly suppressed. The leaves are leathery. The perianth segments are either all the same size, or else the ones forming the inner ring are larger. The illustrated species is a rather small plant with a rosette of small leaves. The flowers are white and each perianth segment “has pale pink transverse stripes. It is native to the Moluccas.

In its native habitat, P. amboinensis grows on the trunks of trees in shade and in a humid atmosphere. As a result, it is sensitive to dry conditions and low temperatures. In winter it requires a temperature of 17°-21 °C (63°-70°F). Keep the root ball constantly wet. The temperature must be increased from spring onwards. By summer it should reach 28°C (82°F) in the shade; at night it should not fall below 20°C (68° F). The plants do well in baskets or perforated pots in a mixture of osmunda root, fresh sphagnum moss and crushed beech leaves. They should be watered only with soft water. The atmospheric humidity should be at least 60 per cent but 70 per cent is preferable.

Vanda teres

Vandas are readily identified even outside the flowering period by their erect stems, up to 1 m (39 in) high, covered with alternate leaves on two sides, and numerous aerial roots. There are some 60-70 species of Vanda distributed from India to New Guinea. The perianth segments are almost identical and narrow towards the base in a shape like a fingernail. The lip has a short spur, the middle lobe is kidney-shaped.

It stands up well to direct sun, requiring light shading only on the hottest summer days. Maintain a temperature of about 25°-27°C (77°-81°F). Mist frequently to provide high humidity. In late summer, limit watering and reduce the temperature to 17°-22°C (63°-72°F). Too little light and warmth prevent the plants flowering because the buds drop prematurely.

Vanda x rothschildiana: This hybrid species is derived from crossing V. coerulea with V. sanderana. It is particularly in the large-scale cultivation of Vandas that use is made not only of interspecific, but also of intergeneric hybrids. Vanda species are most often crossed with species of the genus Ascocentrum; the resulting intergeneric hybrid is designated x Ascocenda. It is distinguished by large flowers, striking colours, and smaller habit. This hybrid is noted for its large flowers, 8-15 cm (3-6 in) across, which are a lovely amethyst blue with darker markings. They are relatively long-lasting.

Vandas can readily be propagated by vegetative means. There are two methods. The first is by detaching the sideshoots produced by older plants as soon as they form their own roots. The second method is by dividing the stem if it has already formed aerial roots along its length. Cut off the top part of the stem and insert it in a growing medium. Leave the lower part in the original substrate, where it will soon produce a new sideshoot.

Vanda tricolor var. suavis

This species is found only on the island of Java. It is extremely variable and several sub-specific units have been described, one of them being the illustrated variety. The stem may be as much as 1.5 m (59 in) high and is thickly covered with leaves. The leaves are strap-shaped and 30-50 cm (12-20 in) long. The inflorescence overtops the leaves and is composed of eight to ten flowers. These are about 7 cm (2 ¾ in) across and pleasantly scented. The flowering period is from May to September.

For good growth, provide a free-draining substrate, such as a coarse mixture of fern roots, crushed oak bark, fresh sphagnum moss and organic fertilizer. This orchid requires a very humid atmosphere. Do not reduce watering until late summer. In winter it requires a temperature of 17°-22°C (63°-68°F). If the plant does not produce flowers it is usually because it lacks sufficient light; if the buds drop, that is the result of too cool conditions.

Coelogyne pandurata

This species is native to Borneo and Sumatra, where it grows on trees alongside rivers. The pseudobulb is cylindrical and produces two leaves about 35 cm (14 in) long. The very fragrant flowers are arranged in loose, drooping inflorescences.

Because it is an epiphytic orchid, it requires a light and aerated substrate for good growth – a mixture of fern roots, crushed oak bark, fresh sphagnum moss and organic fertilizer is ideal. Some species grow well in a flat dish. All require adequate ventilation. They may be grown in a plant-case and also on a flower stand by a window.

Lycaste aromatic

The genus Lycaste is native to tropical America. It was named after Lycaste, daughter of Priam, the legendary king of Troy at the time of the Trojan war. It includes about 35 species that mostly grow as epiphytes on trees. The ovoid pseudobulbs with two thin, deciduous leaves, are characteristic. The numerous flowers are long-stalked, about 3-5 cm (1-2 inch) across and very fragrant. It requires a lightly shaded position and nourishing, but free-draining, compost. A good mixture is fern roots, fresh sphagnum moss, leaf mould or rotted turves, charcoal and crushed brick. Provide plenty of ventilation and mist the plant liberally during the growing period. After the leaves have dropped, mist just enough to prevent the pseudobulbs shrivelling and drying up.

Pleione formosana

Pleiones include both epiphytic and terrestrial orchids, found in the mountains of Asia from the Himalayas to Taiwan. They have globose or ovoid pseudobulbs from which grow narrow leaves and scapes. The leaves are slightly leathery and drop before the resting period. The flowers grow singly or in pairs. The species illustrated is large compared to others in the genus; the pseudobulbs are up to 10 cm (4 in) across, the leaves up to 35 cm (14 in) long and the flowers may be up to 10 cm (4 in) across.

During the growing period, keep the plant at normal room temperature. After the leaves have dropped, the temperature should be slightly lower. Pleiones are not very pretty when they have finished flowering and, therefore, it is advisable to move them to a partially shaded spot in the garden. They must be sheltered from direct sun. The pseudobulbs should be overwintered in a cellar and watered sparingly. As soon as they begin new growth, move them to a window and water liberally. Propa gation is by the readily produced small pseudobulbs, called bulbils.

Dendrobium nobile

The vast number of species – some 2,000 – indicates the variability of this genus. Dendrobiums are epiphytic orchids found from the Himalayas to Japan and southward to New Zealand. The stem of D. nobile is up to 60 cm (24 in) high, fleshy, and covered with narrow leaves that remain on the plant for two years. The flowers usually grow in twos or threes from the nodes and are 7-10 cm across.

This orchid does well indoors. After flowering, it should be watered sparingly until new shoots begin to form. Moving the plants to a shaded spot in the garden for the summer has proved to be very beneficial.

Dendrobium victoriae-reginae

This is a very ornamental member of the large genus Dendrobium. The generic name means ‘living on a tree’ (The Greek dendron = tree and bioein= to live), reflecting the epiphytic way of life of all these orchids. The flowers with their large, spreading petals are typical of D. victoriae-reginae.

Repot only after two years. It is better to put the plants in a smaller container in a free-draining substrate. Even though they require a great deal of water, the soil must not be sodden. Hard water is very harmful. Dendrobiums require a humid atmosphere for a good growth – a relative humidity of about 50 per cent in winter and 70 per cent in summer should be provided; use rainwater if possible.

Phragtn opedium longifolium

This species is found in rather damp, rocky habitats in Costa Rica, Panama and Colombia. It may occur at elevations of up to 2,000 m (6,600 ft) and grows either as an epiphyte on old trees or as a terrestrial orchid in humus-rich soil. The structure of the flowers resembles that of the flowers of the related genus Paphiopedilum. The two side segments are very narrow and long, coloured violet, and loosely coiled in a spiral. The central segment is upright and brown in colour, with darker, longitudinal stripes. The lip is large, pouch-like, coloured yellow edged with white and with green markings inside. The stem is thickly covered with numerous leathery leaves.

It likes cool conditions – a temperature of about 23° C (73° F) in summer and 15°-l8°C (59°-64°F) in winter. Ventilate well and mist frequently.

Brassia verrucosa

The flowers measure up to 10 cm (4 in) and have long, extremely narrow segments coloured yellow-green with minute black spots. The lip, shaped like a cornucopia, is white with brownish markings. Unfortunately, these ornamental blossoms have an unpleasant odour. The inflorescences, composed of 10-15 flowers, are up to 60 cm (24 in) long.

This orchid should be grown at normal room temperature, but requires a markedly cooler temperature at night. Ventilate well. Water freely from spring to autumn, and more sparingly in winter; never allow the compost to dry out. Use only soft water.

Propagate the plants when repotting; detach and plant healthy pseudobulbs, which will soon form new plants.

Ansellia africana

Ansellias are native to tropical Africa. There are only six species, A. africana being the most familiar. It is an epiphyte with firm, grooved stems and narrow leaves, up to 40 cm (16 in) long, with five pronounced ribs. The inflorescences are branched, more than 50 cm (20 in) long, the flowers 4-6 cm across.

It thrives indoors and forms upward-growing aerial roots. Maintain a maximum summer temperature of 20°C (68° F) and water liberally. Late summer marks the beginning of the rest period; reduce watering and provide the plant with cooler conditions, about 16°-20°C (61°-68°F).

Vuylstekeara

This orchid is a triple intergeneric hybrid derived from Cochlioda x Miltonia x Odontoglossum and developed in 1912. It grows to a height of more than 1 m (39 in) and the size of the inflorescence is about 75 cm (30 in) in length.

It grows well indoors if placed in a window. In winter, maintain a daytime temperature of about 18°C (64° F) and a nighttime temperature of 13°C (55° F). Liberal watering is essential, as the plant must not be allowed to dry up even in winter.

Epidendrum cochleatum

The genus Epidendrum includes 1,000 species distributed in the tropical and sub-tropical regions of the Americas. The generic name is of Greek origin and means ‘on a tree’ (epi = on, den-dron = tree), suggesting that members of this genus are epiphytes. They have narrow pseudobulbs, leaves that, as a rule, are leathery, and terminal inflorescences. E. cochleatum has pseudobulbs about 10 cm (4 in) long, bearing two leaves. These are elongate, about 20 cm (8 in) long. The upright inflorescences are usually composed of five to eight flowers. The perianth segments are linear, up to 4 cm (IV2 inch) long, and coloured white and green; the lip is violet and black, marked yellow. Provide the plant with light to partly shaded conditions and a normal room temperature; in winter the temperature should not fall below 15°C (59° F). During the growing period, water when the surface of the compost is dry. Limit watering as soon as the shoots ripen in the autumn. Propagate the plant when repotting by detaching healthy pseudobulbs which may develop into flower-bearing plants within two to three years.

Odo toglossum cervantesii

This orchid grows as an epiphyte in the mountain forests of Mexico and Guatemala. The pseudobulbs are small, 2-3 cm long, slightly compressed and faintly angled in the lower part. A single leaf, 10-15 cm (4-6 in) long, grows from the top of the pseudobulb. The flowers, are arranged in racemes that are always pendent. They are 4-6 cm across, white, occasionally tinged with pink, and with brownish-violet stripes at the base of the segments.

This species requires a relatively low temperature in winter 14°-16°C (57°-61°F) in the daytime, 12°C (54°F) at night. It is readily propagated by detaching the pseudobulbs when repotting. Wrap sphagnum moss round the pseudobulbs and put them in a plastic bag until the first roots appear.

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