The first botanical gardens and collections of preserved plants in the 16th century served didactic purposes and should ensure correct identification of medicinal, ornamental and other useful plants. Collections of preserved plants were nearly all book-herbaria, emulating illustrated books and owned by individual botanists. Curiosity cabinets of nobles and prominent scholars were larger collections, in which all kinds of objects of natural history from remote regions could be incorporated. The Linnaean revolution favoured loose-leaf herbaria over the old book-herbaria: herbaria with loose sheets could be reorganised in agreement with new knowledge or theories and newly accessed
specimens could be placed next to earlier ones of the same species. However, the Linnaean collections reflected the essentialist species concept, according to which all species consisted of individuals with similar essence and separated from other species by sharp discontinuities. Therefore only few specimens were accumulated per species. A.P. de Candolle saw the need for the study of variation within species and stressed the importance of many specimens per species. The Darwinian revolution in 1859 further increased that trend, requiring more specimens to allow the study of variation both within and between species. During the 19th and the 20th centuries larger botanical gardens and large public herbaria with tropical plants developed in European countries, particularly
in countries with tropical colonies, eventually also in the United States and in
some tropical countries, for example in Brazil (Rio) and India (Calcutta). Before and particularly after World War II new botanical gardens and herbaria were established in the tropics and the collections in Europe and North America continued to grow, facilitated by easier travelling and growing interest in exploring the World’s biodiversity. New trends in the 21st century included a wider focus than the study of taxonomy and plant geography: for example conservation and climate change. Many factors may influence the future of tropical plant collections: the influence of growing world population and increasing urbanisation on conservation, increasing focus on technologically
complex disciplines in the utilisation of collections and an increasingly complex international legislation, such as the Washington Convention, the Convention on Biological Diversity, and the Nagoya Protocol on Access and Benefit-sharing.