Coffea

Lore & Background

The genus Coffea was first described by Carl Linnaeus in 1753, with Coffea arabica as the type species. New species continue to be identified; in 2008 and 2009, researchers from the Royal Botanic Gardens, Kew named seven species from northern Madagascar, including C. ambongensis and C. boinensis. In 2008, a new caffeine-free species, Coffea charrieriana, was discovered in Cameroon, followed by Coffea anthonyi in 2009. Around 2011, Coffea absorbed most species of the former genus Psilanthus (roughly 20–24 species) based on phylogenetic evidence, expanding the genus and extending its native distribution to tropical Asia and Australasia.

The coffee genome was published in 2014, revealing over 25,000 genes and showing that coffee plants make caffeine using a different set of genes from those found in tea and cacao. A robust phylogeny of the entire genus was published in 2017, suggesting Africa or Asia as the likely ancestral origin and pointing to several independent radiations across Africa, Asia, and the Western Indian Ocean Islands. In 2020, a technique of DNA fingerprinting was proven effective for coffee, potentially allowing improvements in pest and disease susceptibility information, seed system professionalization, and traceability for buyers.

Reader's Guide

Coffea ranks as one of the world's most valuable and widely traded commodity crops, serving as an important export product for countries in Central and South America, the Caribbean, and Africa. The coffee trade relies heavily on two species: Coffea arabica (Arabica), accounting for about 55% of world production, and Coffea canephora (Robusta), accounting for about 45%. Arabica is preferred for its sweeter taste, while Robusta has higher caffeine content. Both species are vulnerable to shifts in growing zones caused by climate change, likely resulting in production declines in some important regions.

The genus includes over 130 species, many of which contain caffeine as a natural defense against pests, while also attracting pollinators like honeybees. Caffeine has evolved independently in multiple Coffea lineages and in the more distantly related genera Theobroma (cacao) and Camellia (tea). The discovery of caffeine-free species like Coffea charrieriana and self-pollinating species offers potential for introducing new traits to cultivated coffee. The fruit and leaves also contain caffeine and are used in beverages such as coffee cherry tea and coffee-leaf tea.

Did You Know?

• The coffee plant is neither a true cherry nor a true bean; the fruit is an epigynous berry or indehiscent drupe.
• About 5–10% of coffee fruits contain only a single bean, called a peaberry, which is smaller and rounder than a normal coffee bean.
• Coffea arabica trees produce fruit after three to five years and can produce for 50 to 60 years, with up to 100 years possible.
• Caffeine in coffee serves as a toxic substance that protects against insects and simultaneously attracts honeybees by creating an olfactory memory.