Coffea

Lore & Background

The genus Coffea and the type species Coffea arabica were first described by Carl Linnaeus in 1753. New species of Coffea are still being identified in the 2000s. In 2008 and 2009, researchers from the Royal Botanic Gardens, Kew, named seven from the mountains of northern Madagascar, including C. ambongensis, C. boinensis, C. labatii, C. pterocarpa, C. bissetiae, and C. namorokensis.

In 2008, two new species were discovered in Cameroon: Coffea charrieriana, which is caffeine-free, and Coffea anthonyi. In 2011, Coffea absorbed the twenty species of the former genus Psilanthus due to the morphological and genetic similarities between the two genera. This transfer expanded Coffea from 104 species to 124, and extended its native distribution to tropical Asia and Australasia.

The coffee genome was published in 2014, with more than 25,000 genes identified. A robust and almost fully resolved phylogeny of the entire genus was published in 2017. In 2020, a technique of DNA fingerprinting, or genetic authentication of plant material, was proven effective for coffee.

Reader's Guide

When grown in the tropics, coffee is a vigorous bush or small tree that usually grows to a height of 3 - 3.5 m. Most commonly cultivated coffee species grow best at high elevations, but do not tolerate freezing temperatures. The white flowers are highly scented. The trees produce edible red or purple fruits that are either epigynous berries or indehiscent drupes.

The fruit is often referred to as a 'coffee cherry', and it contains two seeds, called 'coffee beans'. The fruit takes about nine months to ripen. In any coffee crop, about 5–10% of fruits contain only a single bean, called a peaberry. The Coffea arabica tree grows fruit after three to five years, producing for an average of 50 to 60 years, though up to 100 years is possible.

There are over 130 species of Coffea, which is grown from seed. The two most popular are Coffea arabica (Arabica), which accounts for around 55% of the world's coffee production, and Coffea canephora (Robusta), which accounts for about 45%. C. arabica is preferred for its sweeter taste, while C. canephora has a higher caffeine content. C. arabica has its origins in the highlands of Ethiopia and the Boma Plateau of Sudan, and came about as the result of a hybrid between C. canephora and C. eugenioides.

Did You Know?

• The caffeine in coffee beans serves as a toxic substance that protects against insects and other pests, and simultaneously attracts pollinators, specifically honeybees.
• Caffeine has evolved independently in multiple lineages of Coffea in Africa, and also in the more distantly related genera Theobroma (cacao) and Camellia (tea).
• Several insect pests affect coffee production, including the coffee borer beetle (Hypothenemus hampei) and the coffee leafminer (Leucoptera caffeina).
• Coffee is used as a food plant by the larvae of some Lepidoptera species, including Dalcera abrasa, turnip moth, and some members of the genus Endoclita.