Growing coffee

The number of species in the coffee genus has increased from 104 to 124 as a result of a new systematic study.

Map icon
View on map: UK - Kew Gardens,

25 Jul 2012

  •  
  • Close Thanks for liking this page. Tell us why by adding a comment at the bottom.
Coffea mannii

Coffea mannii, formerly the type species of the genus Psilanthus (Image O. Maurin)

The generic delimitation Coffea has troubled coffee researchers and taxonomists for more than 250 years. Only recently has molecular systematic research shown that, of the many genera previously associated with Coffea, only one genus, Psilanthus (20 species), is in fact closely related.

Indeed, some species of Psilanthus have previously been included in Coffea (Davis, 2010), as well as being used as local coffee substitutes and in trials for coffee production. Biological evidence from a variety of other sources also points to a close association between Coffea and Psilanthus, and it has been suggested on a number of occasions that they should be united into a single genus.

Coffea ambongensis
Coffea ambongensis with the fruit cut open to reveal brain-like coffee beans (Image A. Davis)

Psilanthus subsumed into Coffea

The argument has now been settled by research published in the Botanical Journal of the Linnean Society.

Kew scientists Aaron Davis, Nicolas Ruch and Mike Fay, together with James Tosh (Natural History Museum, London), investigated a broad range of Psilanthus and Coffea species in a molecular systematic study that used four plastid regions and one nuclear region in combination with morphological and other biological data. They concluded that Psilanthus should be subsumed into Coffea (Davis et al., 2011).

This decision means that the number of species in Coffea jumps from 104 to 124, and the natural distribution is extended from Africa and the Indian Ocean Islands to include tropical Asia and Australasia (Davis, 2011). The unique defining character of Coffea is the presence of coffee beans.

Item from Dr Aaron Davis (Rubiaceae Team Leader)
Kew Scientist, issue 41


Article references:

Davis, A. P. (2010). Six species of Psilanthus transferred to Coffea (Coffeeae, Rubiaceae). Phytotaxa 10: 41–45.

Davis, A. P., Tosh, J., Ruch, N. & Fay, M. F. (2011). Growing coffee: Psilanthus (Rubiaceae) subsumed on the basis of molecular and morphological data; implications for the size, morphology, distribution and evolutionary history of Coffea. Botanical Journal of the Linnean Society 167: 357–377.

Davis, A. P. (2011). Psilanthus mannii, the type species of Psilanthus, transferred to Coffea. Nordic Journal of Botany 29: 471–472.


More on this story

Kew science project: Coffee phylogeny project

Kew news: Seven species of wild coffee amongst Kew's haul of new discoveries

Background

Kew species profile: Coffea arabica

Kew difficult seeds project: Coffea arabica

Kew species profile: Coffea ambongensis

Kew science project: Baseline data for the conservation and sustainable development of coffee species

Kew science project: Searching for hosts of the coffee berry borer

Related stories

Kew news: Kew's coffee research in Madagascar is helping to save your daily cup


Help Kew break new ground and inspire new generations

By making a donation to Kew today you can help our scientists to find out more about the fascinating world of plants, break new ground and inspire generations of young people to get to know plants better.

Our scientific programmes are focused on understanding plants and conserving the world's plant life and habitats at risk. Plants are essential to life on earth. In a world where the sustainability of the planet’s rich biodiversity is becoming less certain, Kew’s science work is ever more critical. Find out how your donation can make a difference.

Give now and support Kew’s vital plant science work


Browse Kew news




No comments on 'Growing coffee'

See your favourite reasons to visit