The coffee family (Rubiaceae)

Coffee is usually associated with the world’s favourite beverage, but the coffee family itself, the Rubiaceae, is actually one of the least well-known plant families.

The coffee family (Rubiaceae) is the largest woody plant family in the wet tropics, and contains approximately 13,200 species. Most species live in the lower ‘understorey’ level of the forest, where their fruits, nectar and leaves provide an important source of food for animals.

Identifying Rubiaceae

Members of the coffee family are easy to identify by the presence of simple, opposite or whorled, entire leaves, stipules (positioned in between the petioles); and an inferior ovary. The Rubiaceae occur in every region of the world, except for the Antarctic Continent. Species diversity and biomass is distinctly concentrated in the tropics and the subtropics, being less frequent and less diverse in the temperate to the sub-polar regions.

Economically important species

Seeds of Coffea arabica (coffee)

The most economically valuable member of the Rubiaceae is coffee (Coffea), which is usually the second most important traded commodity after oil. Worldwide, more than 25 million people depend on coffee for their livelihoods. Other commercially important members of the family include:

Cinchona (quinine)
Pausinystalia johimba (yohimbe, an aphrodisiac)
Rubia tinctoria (madder, a dye)
Genipa (genipapo, a fruit used to make a beverage and a dye)
Uncaria gambier (gambier, an important tannin source)
Uncaria (medicines)
Calycophyllum (lemonwood, a timber)
Neolamarckia chinensis (a timber tree)
Gardenia (perfume & ornamentals).

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 coffee species 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 work on the coffee family

On expedition in Madagascar discovering Coffea pterocarpa

Kew botanists on expedition in Madagascar where seven wild species of coffee species were discovered in 2009.

Kew's current work on the Rubiaceae is focused on Tropical Africa, Madagascar, Eastern Brazil, and selected parts of Southeast Asia. At home, Kew houses the world’s most comprehensive herbarium collection of Rubiaceae, and is one of very few institutes that is able to support a worldwide genus/species identification facility for the famil, e.g. for checklists, inventories of tropical regions, and conservation assessments. This is possible due to the strength of the collections, the extremely high standard of curation, and expertise of staff.

Kew’s scientific work on the Rubiceae includes the production of fundamental biodiversity data, which is accessible as monographs, floras, databases and checklists. This data is used for many purposes, including environmental monitoring, plant use, conservation and climate change. One of our most recent significant achievements towards increasing our understanding of the Rubiaceae is the online publication of the World Rubiaceae Checklist, which provides essential information for each Rubiaceae species.

Kew is also a world leader on the study of wild coffee species, with staff members describing more than 30 of the 103 species now known to science, with 21 new species discovered in the last 10 years alone.

In particular Kew is committed to providing information for the conservation of wild coffee genetic resources, including data from genetic (DNA) studies and satellite imagery. Knowledge of wild crop relatives is essential for the long-term sustainability of agricultural commodities, such as coffee, particularly in an era of local and global climatic change.