Rubiaceae
Introduction
The Rubiaceae (coffee family) is the largest and most poorly known woody plant family in the wet tropics. It contains approximately 13,200 species in 620 genera, of which 26 genera have more than 100 species. Psychotria has more than 2,000 species, which is larger than most plant families. Recent inventory studies and rapid biodiversity assessments undertaken in the Old World Tropics, show that 10 to 20% of the total species diversity in some areas is from the Rubiaceae. Not only is the family significant in terms of biodiversity, but it also constitutes a large percentage of total biomass in tropical ecosystems. There are numerous hotspots of Rubiaceae diversity in the wet regions of the Old and New World Tropics (e.g. East and West Africa, Madagascar, SE Asia, Brazil, Costa Rica, Cuba, Peru and Ecuador), and also in the drylands of Madagascar, Angola, and Central America.
The need for further research on the Rubiaceae is substantial. For some regions the extent of ignorance is alarming and there is a clear lack of fundamental data, particularly in the Old World Tropics (mainly Madagascar and SE Asia). The current classification of the family is unstable, although great progress is being made with molecular systematics. There are numerous unresolved generic complexes (including the subfamilies, tribes, and subtribes), many undescribed genera, and several hundred undescribed species. There are more than 200 species without scientific names in Madagascar alone. The need for basic taxonomic knowledge is heightened by habitat destruction in the tropics.
Most species of Rubiaceae occur in the forest understorey, where their fruits, nectar and leaves provide important food resources for animal communities. The most economically valuable genera are Coffea spp. (coffee), Genipa spp. (genipapo, a fruit used to make a beverage and a dye), and Cinchona spp. (quinine). Species of commercial importance include Psychotria ipecacuanha =Carapichea ipecacuanha (ipecacuanha, an expectorant), Pausinystalia johimba (yohimbe, an aphrodisiac), Rubia tinctoria (madder, a dye), Uncaria gambier (gambier, an important tannin source), Uncaria spp. (medicines), Calycophyllum spp. (lemonwood, a timber), Neolamarckia chinensis (timber tree), and Gardenia spp. (perfume & ornamentals). Coffee is by far the most economically important member of Rubiaceae, being the second most important traded commodity after oil. Worldwide, more than 25 million people depend on coffee for their livelihoods. Rubiaceae also provide local indigenous populations with remedies against malaria and other diseases, body paints, edible fruits and construction wood. Most species of Rubiaceae are indicators of forest health and condition. For example certain species of coffee will only grow in good quality, primary forest. Given the abundance and ubiquity of this family in humid and dry tropical forest ecosystems, the identification of Rubiaceae is often vital to the understanding of tropical ecology.
Kew's current work on the Rubiaceae is focused on Tropical Africa, Madagascar, Eastern Brazil, selected parts of SE Asia, and Australia. Our research foci are either not duplicated elsewhere or we are undertaking research in collaboration with other organisations.
Kew houses the world’s most comprehensive herbarium collection of Rubiaceae, and it is the only institute able to support a worldwide genus/species identification facility for the family (e.g. for checklists and inventories of tropical regions). This is possible due to the strength of the collections, the extremely high standard of curation, and the expertise of staff. Other important resources include specimen and taxon databases, a species-level checklist, a bibliographic database, and a generic classification/distribution database. Affirming the position of Kew as a major centre for Rubiaceae taxonomy and systematics, Rubiaceae was made one of the five Dicot Systematic Teams in 2001 as part of the Herbarium restructuring.
The main objectives of the Rubiaceae team are to: 1) continue its world-class baseline plant diversity research (taxonomic studies, monographs, Floras, databases, and checklists); 2) use the products of survey and inventory work for conservation and environmental monitoring (focusing on Madagascar, Africa and Brazil); 3) to maximize access to and use of Kew’s resources (collections, expertise, fundamental research products); 4) work closely with in-country partners; undertaking training and other forms of capacity building where necessary and appropriate; 5) develop and broaden its role in multidisciplinary comparative research.