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The Americas

The mention of Central and South America immediately conjures up images of exuberance and flamboyance, qualities which are also true for the colourful orchids of these regions. Many species from these areas, particularly in the Cattleya alliance, Brassavola, Laelia, Epidendrum, Broughtonia, Sophronitis, Schomburgkia and others, and in the Odontoglossum alliance, which includes Brassia, Ada, Oncidium, Cochlioda, Miltonia and Miltoniopsis, have been used intensively in hybridising programmes in the quest for larger, more vigorous and more colourful flowers. The hybrids are not well represented in the Kew collection, where priority is given to natural species of wild origin, but some are welcome additions and are used for the display in the Princess of Wales Conservatory.


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Terrestrials

As in other parts of the world, the proportion of terrestrial orchids in the flora is lower nearer the Equator and greater in temperate regions. The dove orchid, Peristeria elata is the national flower of Panama. The plants are robust with fat, round pseudobulbs, and the deciduous leaves are wide and plicate. The waxy, white flowers are cup-shaped, about 4 cm across, and have a wonderful fragrance. In cultivation Peristeria needs conditions similar to those of its natural habitat. It is grown in a semi-shaded position in a glasshouse with a winter night minimum temperature of 18ºC (64ºF). In its native forests this species grows among the surface litter, so it is grown at Kew in shallow clay pans half filled with broken crocks to give perfect drainage, and a compost containing a high proportion of leaf mould.

Stenorrhynchos speciosum is grown in a similar way as it has been recorded growing as a terrestrial as well as lithophytically and as an epiphyte in the damp forests of Mexico. It is not commonly cultivated and deserves to be much better known. Its low growing, dark green leaves surround the scarlet flower spikes during the winter. The small red flowers are enhanced by the long, scarlet bracts so that the inflorescence as a whole creates a very fine display.

Some of the South American slipper orchids in the genus Phragmipedium are terrestrial whilst others are lithophytic or epiphytic plants. Phragmipedium schlimii grows in earth and on rocks in the forests of Colombia. Its grassy leaves attain 30 cm in length, and the flower spike is about 30 cm tall. The flowers are white and quite downy in texture, about 4 cm across, with a deep pink lip that nearly hides the yellow staminode. Phragmipedium longifolium forms a tussock of glossy, dark green foliage with arching leaves up to 1 m long. The flowers on each spike open in succession so a mature plant with several flowering growths is rarely out of flower. Each flower is about 6 cm across, suffused with a pale apricot colour and veined with green. The margins of the petals are touched with pink and white and the staminode is yellow. This species grows in Ecuador, Colombia, Panama and Costa Rica, and is terrestrial or occasionally epiphytic.

Phragmipedium caudatum is one of the most interesting species, with incredibly long petals. After the flowers open the petals continue to grow downwards, twisting as they do so, and may reach a length of 1 m. Early illustrations of the species in cultivation show heaps of coiled petals lying on the table. It is said that in the wild the petals continue to elongate until they touch a solid surface from which pollinating insects can crawl up and into the flower. The flowers are greenish yellow with darker green veins and a red hairy margin to the petals. This species grows as an epiphyte in Peru, Ecuador and Mexico. In cultivation, P. caudatum and P. schlimii are grown in a semi?shaded position in a cool?intermediate glasshouse with a winter night minimum temperature of 14ºC (57ºF) and plenty of ventilation. Phragmipedium longifolium is grown under warmer and more humid conditions with a winter night minimum temperature of 18ºC (64ºF). They are all grown in pots in a medium grade epiphyte compost to which has been added peat, chopped sphagnum moss and dolomite chippings to give a slightly alkaline medium. Plants of P. longifolium' planted out in the Princess of Wales Conservatory grow more vigorously than those which are pot grown.


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Epiphytes

The epiphytes of Central and South America present an eye-catching, colourful display of flowers throughout the year.

The genus Cattleya contains over 60 species, many of which have been used to breed hundreds of hybrids. In order to flower well, cattleyas require a great deal of sunlight. They are grown in pots of medium or coarse compost which allows very good drainage and are repotted before the compost starts to break down. Their flowering season begins in the autumn, when C. bowringiana comes into flower. This species has an arching spike of up to 10 flowers each 6 cm across, rosy mauve with darker markings on the lip and a white throat. Cattleya skinneri is very similar but flowers in the summer. Cattleya mossiae, from Venezuela, flowers in spring and has much larger pale pink flowers with a splash of orange and deep pink veining on the lip. Cattleya percivaliana has narrower petals with a deep pink lip. Cattleya maxima seems to have rather weak stems which need staking but its intricate pattern of deep pink veins along the lip makes a very attractive flower. Cattleya warscewiczii is also pale pink with a darker pink lip but the form Frau Melanie Beyroudt is more interesting with almost white petals and sepals and a deep pink lip. Cattleya iricolor from Ecuador is rare, both in cultivation and in the wild. Its petals and sepals are long and narrow and open rather rolled back at the margins so as to appear even narrower. They are a golden colour except for the lip which is cream on the outside and bright gold with red markings inside.

Both the Brazilian and the Mexican laelias. are grown with the cattleyas, although the latter would grow well at lower temperatures. They have a similar requirement for bright sunlight, and flower most prolifically if their leaves are illuminated to the extent that they become suffused with purple. The Mexican laelias, have a distinct resting period when they need to be kept dry and they seem to grow best in shallow, slatted wooden baskets. A number of species have been tried on cork oak bark and Laelia rubescens flowers well in this way. This species is an epiphyte of dry woodland in Mexico, Costa Rica and Panama and is usually found growing at quite high altitudes and in very exposed positions. Its flower spikes form in the autumn and a cluster of up to seven flowers is produced at the end of each one. The flowers range in colour from white through pink and Laelia anceps, an epiphyte from Mexico, grows easily in cultivation and flowers in December every year. (Illustration from Warner and Williams' The Orchid Album, 1888.) RBG, Kew lavender to mauve. Sadly they seem to last for only a few days under Kew conditions.

Laelia anceps has been found in both cool and warm areas of Mexico and seems to be tolerant of various methods of cultivation. It is easily recognised by its one?leaved, angled pseudobulbs and flower spikes up to 1 m long which are produced early in winter. There are one or several flowers, each about 10 cm across, rosy pink, rich pink inside the velvety lip and with deeper coloured veins and a yellow callus. Many different colour variants have been described, including a number of white forms, sometimes with coloured markings in the lip. Laelia gouldiana is rather similar, but the pseudobulbs bear two or three leaves and the flowers are more rounded. This orchid has sometimes been thought to be a natural hybrid between L. anceps and L. autumnalis but is now regarded as a distinct species. The petals are rosy pink with a darker pink stripe down the centre, while the lip is dark pink with even darker veins and a central yellow spot.

At Kew stanhopeas and gongoras are grown in semi? positions in a glasshouse with a winter night minimum temperature of 15ºC (60ºF) and high relative humidity. All the species are vigorous growers and seem to benefit from frequent foliar feeds. On completion of the growth of the new pseudobulb, a short, dry rest is given to the plants but otherwise they like liberal amounts of water. Early attempts to grow stanhopeas were disappointing because, although the plants produced lush foliage, no flowers were seen. Once it was discovered that the plants had flowered, but their flower spikes grew vertically downwards into the compost, success was assured by growing the plants in slatted wooden baskets. The flower spikes can easily push between the slats and the mature flowers hang below the basket. The gongoras seem to thrive best in mesh plastic pots. Their pendent inflorescences arch outwards from the base of the pseudobulbs. A medium grade epiphyte compost is suitable for plants in both genera.

The fat buds of the stanhopeas spring open with an audible popping sound to produce the extraordinary waxy flowers, which have an overpowering fragrance. Stanhopea ecornuta has creamy yellow coloured flowers with purple spots and a strong scent of pinewoods in spring. This species, which originates from Costa Rica and Guatemala, has individual flowers up to 9 cm across. Stanhopea wardii has cream?coloured flowers with red spots and comes from Mexico. Stanhopea tigrina is possibly the most striking species in the genus with cream?coloured flowers in which, again, the cream is nearly obscured by the large red blotches all over the flower. Sadly the Stanhopea flowers do not remain fresh for more than about three days, though they are very spectacular while they last.

The gongoras have smaller flowers but there are usually at least a dozen on each stem and they last for several days longer than stanhopeas. Gongora galeata is a pale brown colour with a vivid orange lip. This species, which comes from Mexico, has a fragrance of oranges. Gongora quinquenervis from Colombia and Ecuador is also scented and has yellow flowers covered in a profusion of red spots.

Paphinia cristata from Colombia is closely related to the gongoras and stanhopeas and is grown in similar conditions. The flowers are large compared with the size of the plant and last for several weeks. They are purplish brown with yellow stripes and very eye catching.

Oncidium is one of the largest Central and South American genera containing about 750 species. Some of these are highly specialised in their range and habitat requirements. Oncidium onustum, for example, grows as an epiphyte only on certain cacti in the coastal desert of Peru and Ecuador. Others are more widespread and tolerant. At Kew most of the oncidiums are grown under intermediate conditions, with a high humidity and high light levels.

The tiny flowers of 0. parviflorum are 1 cm across but cluster thickly around a flower spike about 1 m long and make a pretty display. This is a species from the higher altitudes of Panama. Oncidium cheirophorum from Colombia and Panama is tiny in every way. Its leaves grow up to 6 cm long and its flower spikes arch out, up to about 20 cm long. The tiny, frilly, yellow flowers have the delightful scent of winter sweet. Oncidium splendidum from Mexico, Honduras and Guatemala has thick hard leaves and a tall branching flower spike that carries a striking display of red and yellow flowers. It is short, however, in comparison with 0. cocciferum from Ecuador, in which the flower spike, even on a small plant, is several metres long and frequently twists around the internal struts in the glasshouse on its way to the roof. Its flowers are rather small and widely spaced and are reddish brown in colour with yellow tips to each sepal and petal.

The most spectacular flower is borne by Psychopsis papilio, formerly known as Oncidium papilio, and commonly called the butterfly orchid. In this species from Trinidad and western South America the lovely red and yellow lip and sepals are thought to resemble the wings of the butterfly and the narrow petals its antennae. The flower is held aloft on a slender stem and flutters in the air currents. Each flower is about 10 cm across.

One of the very tiniest orchids in the Kew collection, Psygmorchis pusilla, is closely related to the genus Oncidium. This delightful plant forms a fan of foliage about 4 cm across and up to four flowers grow on each short flower spike. Each flower is 2 cm across and pale yellow with brown spots towards the centre. This species is a twig epiphyte in the humid forests and plantations of Mexico.

The Odontoglossum alliance includes the genera Lemboglossum, Osmoglossum, Rossioglossum, Cuitlauzina, and Miltonia as well as Odontoglossum, and others, which have all been hybridised intensively. At Kew the original species are cultivated together with a few
hybrids which enhance the displays in the Princess of Wales Conservatory. The lemboglossums all come from high altitudes in Mexico and Guatemala and at Kew are grown in a cool airy glasshouse with a winter night minimum temperature of 14ºC (57ºF). They are potted in the smallest containers able to accommodate their roots, using a medium epiphyte compost. Lemboglossum cervantesii has white or pale pink flowers about 6 cm across with concentric circles of maroon bars around the column. Lemboglossum bictoniense has a broad pink lip with green and red mottled sepals. There are some fine and distinctive colour forms including L. bictoniense var. alba in which the lip is white and the sepals pale green. The star?shaped flowers of L. maculatum have red sepals and white petals spotted with red. Rossioglossum splendens, another Mexican species, is variable in colour but in some forms has flowers of a blazing orange colour with a yellow lip marked with red spots.

One of the largest genera, whose species occupy a wide range in the Americas, is Epidendrum. It is extremely variable in size and form and contains many species with very attractive flowers. Epidendrum ilense was discovered in 1976 in the Montanas de Ila of Ecuador in an area of felled woodland. Four plants were rescued from the area and seeds and seedlings from these were distributed from the Marie Selby Botanic Garden, Florida, in 1980. Some of these were sent to Kew where, in turn, the numbers of plants are being increased so that they can be distributed. Recently this species has been rediscovered in Ecuador but it is considered to be very rare and it is likely that its remaining habitat will be destroyed before the orchid's ecology is fully understood.

Habitat destruction in Central and South America also threatens the future of many of the thousand or so Epidendrum species, only a small proportion of which are in cultivation.

The pale green flowers of E. difforme are curious as they are rather fleshy and appear to be almost translucent. This species is an epiphyte from Florida and Mexico and grows up to 30 cm tall. Epidendrum ciliolare grows as a lithophyte or epiphyte in most of Central America and will form huge clumps if allowed to do so. The flowers are like lime?green stars about 8 cm across and the lip is white with a shaggy fringed margin.

The encyclias were at one time not considered distinct from Epidendrum but are now kept apart because of various characteristics of the flower and their pseudobulbous habit. Encyclia fragrans and E. cochleata were among the first epiphytic orchids to flower at Kew, in 1782 and 1787 respectively. The most striking feature of E. fragrans is its powerful scent which is very strong from a distance of several * metres. Its flowers are whitish green except for the lip on the upper side of the flower which is violet striped. The somewhat similar E. pentotes has probably the strongest, sickly sweet smell of any orchid at Kew

Encyclia cochleata, known as the cockleshell orchid, is widespread from Florida, through Mexico and Central America to Brazil. Its sepals and petals are pale green, slender and reflexed, while the shiny, dark maroon lip stands over the column like a hood. This species grows well in a warm intermediate glasshouse with a winter night minimum temperature of WC (61F) where it rarely stops flowering. Encyclia citrina, from Mexico, is grown in the Cattleya house, with a minimum night temperature of WC (61ºF), and is kept very dry during the winter months. It is grown on cork oak bark and is quite distinctive with its pendent, grey-green pseudobulbs and foliage. The buttercup have the fragrance of lemons and appear in spring. The subtribe Pleurothallidinae is probably the largest single alliance in the American continent. Restrepia, Pleurothallis, Scaphosepalum, Masdevallia, Dracula Stelis and others are included in the Kew collection. The two genera of most horticultural merit are probably Masdevallia and Dracula Both are grown in a glasshouse with a winter night minimum temperature of 14C (57ºF) and both benefit from liberal watering. The draculas are grown in hanging baskets of fine epiphyte compost and hung above head height so that their pendulous flowers can be appreciated. They have three large sepals which form a triangle and a pouch like lip which wobbles in the air currents in a fascinating manner. Dracula chimaera has white sepals which are heavily blotched with red and a white lip. The sepals are dotted with short white hairs. This species originated in Colombia, as did D. bella which has yellow sepals with deep red spots and long trailing tails at the tip of each sepal. The inflated lip is white. The inflorescences of this species emerge from the base of the plant and hang down below the plant in the sunlight.

Although most of the masdevallias are epiphytes they seem to grow best when grown in pots just large enough to accommodate their roots in a fine epiphyte compost. They form neat tufts of attractive green foliage and have one or more colourful flowers on each inflorescence. The petals and lip of each flower are very tiny but the sepals are greatly enlarged and the tins of each are frequently decorated with a slender pointed tail.

In a brief survey, it is impossible to mention more than a few of these increasingly popular orchids. The scarlet Masdevallia veitchiana is probably the best known, and the various colour forms of M. coccinea, white, yellow and magenta, are also commonly cultivated. Masdevallia angulata from Ecuador is a vigorous grower and has rather tubular flowers which are olive?green with deep red blotches. Masdevallia barlaeana from Peru is a vivid magenta colour and flowers over a long period. Masdevallia macrura from Colombia has extraordinary orange flowers with red spots and long twisty yellow tails. It is one of the longest Masdevallia flowers and can measure up to 30 cm from the tip of the tail of the dorsal sepal to the tip of the tail on one of the lateral sepals.

Several of the North American species of Cypripedium are grown amongst the other terrestrial species in a cold glasshouse and also in cold frames in the nursery. The stately Cypripedium reginae forms splendid clumps of stems with attractive pink and white flowers. It contrasts with the smaller and slender C. acaule, which has a large pink lip but smaller, brownish sepals and petals. There are also several different forms of Cypripedium calceolus which have a bright yellow lip and yellow, green or brownish sepals and petals.

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