Tropical Orchids of Southeast Asia. David P. Banks

knowing it. Such tongue-twisting examples include Agapanthus, Bougainvillea, Chrysanthemum, Jacaranda and Rhododendron. These names are derived from both Latin and Greek, however, Latin has been used extensively for scientific terms. This enables a universal system for communication. A problem with common names is that one name may refer to many completely different plants. Also, what may be a "local" name in one area may not be pertinent in another.

      Over 75 per cent of the world's known orchid species occur in the tropics. This is a fact that doesn't surprise many. What may surprise, however, is that the majority of these "tropical" species (over 80 per cent) inhabit the cooler mountainous forests, at altitudes of over 1000 metres above sea level. These montane forests provide homes for an amazing number of diverse and unique plant and animal species. Isolated high peaks, such as Mt. Kinabalu in Sabah, have a high percentage of endemic species that are found nowhere else in the world.

      In the tropics, most orchids are epiphytes, that is, they grow on trees for support and light. They are not parasitic, as they do not take food from the tree. Some species grow exclusively on rocks, and are known as lithophytes. Species that grow in the ground are referred to as terrestrials. Most of the tropical terrestrial orchid species are evergreen, unlike the deciduous terrestrials, which are generally found in more temperate climates. After flowering, these plants die down to storage organs, known as tuberoids, which have a similar life-cycle to bulbs.

      Dendrobium devonianum

      Paphiopedilum druryi

      A small percentage of orchids are saprophytes; these live off dead or decaying matter. There are even two Australian orchid species which grow and flower completely underground!

      Only a small percentage of the world's orchid flora is cultivated in specialist nurseries, botanical institutions and private collections. Whilst the collection of popular species from the rainforests can threaten the survival of wild orchid populations, their main enemy is habitat destruction. Southeast Asia is one of the world's most densely populated regions, and its virgin forest continues to be cleared and burnt. New species continue to be discovered, and a number of "lost" species have been relocated. Yet one wonders how many species, both plant and animal, have become extinct before they have even been recorded.

      Fortunately, most of the horticulturally attractive orchid species are entrenched in cultivation and have been propagated by division or by seed. The species at real risk are the countless miniatures, or "botanicals", as they are known. These have little commercial value and are of most interest to botanists and orchid species enthusiasts.

      Hopefully, this book will dispel the myth that most orchid species look the same. In fact, these wonderful plants come in a huge array of shapes, sizes and colours, and are highly specialised. The tropical orchid species shown of the following pages represent the tip of an enormous iceberg.

      Orchids will continue to captivate future generations with their unique beauty—indeed they are the monarchs of the plant kingdom.

      —David P. Banks

      Aerides

      The name Aerides literally means air-plant. About 20 species belong to this genus of monopodial epiphytes. Many of these sturdy plants are found in the warm lowlands of-the tropics. Most species are easy to grow and have highly perfumed flowers, which has made them popular in horticulture. Aerides odorata is variable in colour, from deep pink to pure white, and is widely distributed throughout Southeast Asia. Albinistic or white-flowered forms of these species are highly prized by collectors. Aerides quinquevulnera is from the Philippines and New Guinea and has waxy pink, spotted to deep purple flowers which can last for over a month in pristine condition. Aerides rosea, from northern Thailand, was formerly well known as Aerides fieldingii. It has long, pen-dent inflorescences of lolly-pink flowers, with some darker spotting on the petals. Aerides species are frequently cultivated, attached to the trunks of trees which will not shed their bark. In optimum conditions, the thick white roots will attach firmly to the host and ramble quite a distance from the plant.

      Many hybrids have been made between Aerides and other members of what are loosely termed the "vandaceous" family. Such combinations include Aeridocentrum (x Ascocentrum), Aeridopsis (x Phalaenopsis), Rhynchorides (x Rhynchostylis) and Aeridovanda (x Vanda). The genus Christieara is a three-way hybrid involving Aerides, Ascocentrum and Vanda. Many of these hybrids come in a wide range of colours due to the high degree of genetic diversity. They also have long-lived flowers, a trait which has made them popular as cut flowers and as flowering pot plants. Some of the other Aerides species in cultivation include A. lawrenciae (which is like a giant A. odorata), A. crassifolia (a fleshy plant with large purple flowers), A. krabiense (deep mauve flowers), the lilac and cream A. falcata, and its close relative A. houlletiana, which has yellow, white and purple blooms.

      Aerides odorata var. alba

      Aerides quinquevulnera

      Aerides rosea

      Aerides quinquevulnera var. purpurata

      Amesiella and Ascocentrum

      Amesiella

      The Philippine species Amesiella philippinensis was known for many years as Angraecum philippinensis. The genus Angraecum is actually restricted to Africa and Madagascar. There are two species in this monopodial genus, with a second species recognised in 1998. Both species are epiphytes which have short spikes bearing up to five disproportionately large crystalline white flowers. Amesiella philippinensis has a prominent yellow blotch on the labellum and occurs at lower altitudes. The more robust Amesiella monticola has larger pure white flowers complete with a differently-shaped, three-lobed labellum and longer spur. This spur is filled with nectar to attract its pollinator, which is probably a moth since the flowers are fragrant at night.

      Ascocentrum

      The monopodial genus Ascocentrum is a group of small, compact plants consisting of less than ten epiphytic species which have played an important part in the development of vandaceous hybrids. Ascocentrum has been bred with members of the genus Vanda to create the artificial genus Ascocenda. The Ascocentrum has helped introduce bright colours to its progeny, while also reducing the plant size.

      Ascocentrum ampullaceum has round, glowing purple flowers and often flowers profusely. Recently, a very rare pure white clone of the species was discovered. White-flowered forms of coloured orchids always demand high prices due to their scarcity. Numbers can be increased by division of older plants, seed and tissue culture. Plants produced by tissue culture, called mericlones, are genetically identical to the parent plant, whereas seedlings may display variation in colour and form. The bright orange Ascocentrum garayi is a popular plant in its native Thailand. For years this species has been confused with the related Ascocentrum miniatum. The miniature Ascocentrum pumilum is endemic to Taiwan.

      Ascocentrum ampullaceum

      Ascocentrum garayi

      Ascocentrum