The first modern botanical gardens were developed in connection with European universities about 500 years ago so that medical students would be able to study the plants that they used for curing people. Plants were the main source of medicines then, as they are still for most people in the world. As the exploration of the rest of the world reached remote continents, many new kinds of plants reached the gardens of Europe, and they increasingly engaged the attention of the general public. Not surprisingly, in view of their origin in universities, botanical gardens from the first were places where research on plants has been conducted, and that trend has continued to the present. Botanical gardens are distinguished from gardens at large by the size and diversity of their living plant collections.
Many of the largest groups of scientists studying plant systematics and evolution are located in botanical gardens, such as the Royal Botanic Gardens, Kew, England; the Komarov Institute of the Russian Academy of Sciences, St. Petersburg; The New York Botanical Garden; and the Missouri Botanical Garden. These gardens sometimes have close connections with local universities, and sometimes are independent. Similar research institutes are also found in natural history museums, which may lack gardens; among these are the Field Museum of Natural History, Chicago; U.S. National Museum of Natural History, Smithsonian Institution; California Academy of Sciences, San Francisco; The Natural History Museum, London. All of these institutions may carry out extensive programs around the world, and with the relative decrease in appointments in systematic and evolutionary botany in universities, they are becoming the major employers for systematic botanists. The introduction of macromolecular analyses for determining relationships among plants, from the individual level to a consideration of relationships between major groups in the determination of the "Tree of Life," is gradually changing the types of research conducted in botanical gardens, as it is generally. Gardens with important research institutes are adding molecular laboratories and hiring staff members who specialize in molecular analysis.
At the same time, modern information technology has radically changed the methods applied to organizing, storing, and retrieving information about plants. Probably more than 100,000 species of plants (of a total estimated at 300,000 known species) are already in cultivation in botanical gardens, and there are probably more than 200 million herbarium species, as well as a very extensive literature. This trend will be accelerated in the future, as it is clearly the only way to make sense of the great quantity of data associated with systematic and evolutionary biology.
The study of living plants in botanical gardens is in theory very important, but often the linkage between those collections and the research conducted at the institution where they are displayed is limited. Nonetheless, there is great potential for such research, especially in botanical gardens such as those at Pretoria, South Africa; Canberra, Australia; the University of California, Berkeley; Santa Barbara Botanical Garden; and Rancho Santa Ana Botanical Garden, where there are very extensive collections of plants from their respective areas. Such collections also can have a great importance for conservation, since species that are endangered or threatened in nature can be cultivated in botanical gardens or conserved in seed banks at low temperatures, thus preventing their extinction even if natural populations fail to survive. Careful physiological and ecological studies of properties of such species will be very useful for their own sake; can be used in introducing them into horticulture; and are of fundamental importance for their conservation, as are studies of their genetic variability and other properties.
It is in their educational role, in combination with their science, that botanical gardens offer most to the general public. In addition, they are delightful places for enjoyment, rest, and contemplation that have a solid place in our society, offering as they do a wide variety of features to a very diverse public.
Peter H. Raven, President, Missouri Botanical Garden