Orchids at Kew Introduction

Introduction

THE ORCHIDACEAE IS THE LARGEST family of flowering plants, with perhaps 25,000 different wild species throughout the world. Every year, as new parts of the tropics and subtropics are explored,
at least 100 new ones are discovered and described. In addition to the wild orchids, nearly 100,000 different crosses of artificial hybrids have been raised in cultivation since the 1850s.

Orchids can be found in every country. Fifty species are known to occur in Britain, and seven species have been recorded within the Arctic Circle. The majority occur in tropical areas, where the forests and grasslands on hills and valleys at widely differing altitudes provide the great variety of habitats which orchid plants enjoy. They grow in the ground - as terrestrials, on outcrops of rock - as lithophytes, and on the branches of trees and shrubs ﷓ as epiphytes.

A few grow as vines, scrambling over cliffs or through the forest canopy. Most are small plants while a few are so large that the combined weight of several plants can bring their forest host crashing to the ground. A very small number have no green leaves and grow as saprophytes, obtaining their nutrients by way of a mycorrhizal fungus from dead or dying material in their immediate environment.

Most orchids are perennial plants with pronounced seasonal habits of growth, resting and flowering. Many produce their blooms after a period of little or no growth because of low temperatures or little light. Hence the spring months are the best time to see a wide variety of orchids in flower.

It is for their exotic flowers that most orchids are cultivated by enthusiasts, amateurs and commercial growers throughout the world. At the Royal Botanic Gardens, however, a collection that demonstrates the extraordinary diversity of the family has always been maintained. Large or small, striking or insignificant, beautiful or bizarre, scented or smelly, there are plants with flowers of every description present in the collection, all tended with equal care.

Every colour is represented in the flowers of this exciting family, while the diversity of shape, size, decoration and design is almost incredible. Yet in spite of their almost infinite variety, each flower is based on the same basic plan. Six colourful parts, three sepals, and three petals, one modified as a lip, surround a central column which bears the pollen and stigma.

The shape and colour of each flower is specifically designed to attract a pollinator, usually an insect, who, in seeking what it perceives as food, alcohol or a mate, will brush against the column of successive flowers and so effect cross-pollination. Thousands of seeds are produced in each orchid fruit or capsule and these are so small and light they are readily dispersed by the wind. For germination each must become established with a symbiotic fungus which helps to sustain growth during the seedling's early life.

Orchids have been grown at Kew since the early days of its history as a royal garden. According to a catalogue produced in 1768, 24 species of orchids were growing here when it was still Princess Augusta's private garden. Later, many plants were added after George III inherited the garden from his mother and on the advice and assistance of Sir Joseph Banks. The gardens changed from private to public ownership in 1840, as a result of recommendations made to the Treasury by John Lindley, whose great interest was botany, especially orchids. The first Director of the Royal Botanic Gardens, Sir William Hooker, had his own private collection of orchids and during the years of his directorship, and that of his son Joseph who succeeded him, the orchid collection at Kew was greatly increased.

Today, the orchid collection continues to expand. At any one time it contains about 20,000 plants and there is always a display of plants in flower for the public to enjoy. Kew attracts more than a million visitors every year who come to enjoy the trees, the green lawns, the Palm House, Pagoda and other historic buildings as well as the great diversity of plants in the 121 hectares. Many visitors also go to Wakehurst Place in Sussex, the garden which Kew has leased from the National Trust since 1965. It has a very different soil and climate and many plants grow there which would not survive in west London.

The policy at the Royal Botanic Gardens has always been to display plants of scientific and economic interest in a variety of pleasing ways, but the extensive gardens are, primarily, a scientific collection: maintained for research in several fields of botany and a centre for the distribution of plant material, both decorative and economic. More than 85,000 different taxa in some 340 plant families are grown at Kew and Wakehurst Place, among which nearly 4,000 different species of wild orchids are represented, with plants from every continent and many different habitats. Manmade hybrids are present, too, in limited numbers, and with these the emphasis is on cultivars of important genera which are of historic importance in the breeding of modern hybrids.

The main objective in cultivating a wide range of orchid plants is to provide material for scientific research. Increasingly, the orchids provide a source of germplasm for species which have become endangered in the wild, or may become so. This book describes the orchid collections at Kew and Wakehurst Place and the work associated with them today, as well as providing a look at the way the collections, and various features associated with them, have grown and changed over a period of more than 250 years.

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