Theobroma cacao L. (Malvaceae)



Illustration of Theobroma cacao from Mark Catesby's The natural history of Carolina, Florida, and the Bahama Islands (1754; vol. 1, t.106). Young leaves of Theobroma cacao growing in Trinidad.

Theobroma cacao is the Latin name of one of the world's favourite plants. It is neither the most beautiful nor the most abundant, but it provides us with the raw materials to create a popular snack food, chocolate! It was given its scientific name by Swedish botanist Carolus Linnaeus in his Species Plantarum (1753). The literal translation of Theobroma is 'Food of the Gods', whilst cacao is derived from the Nahuatl (Aztec) word xocolatl which means 'bitter water'.

Genetic studies reveal that the cocoa tree is native to the Amazon region, and that it was distributed by man throughout Central America before Columbus's arrival. Today, the majority of the world's cocoa trees are grown in West Africa. Cocoa trees grow up to eight metres tall, and are part of the rainforest understorey. Their leaves are up to 20 cm long, with long drip tips on the ends to help prevent water accumulation. The pinkish-white flowers grow directly from the branches and trunk, and are pollinated by Forcipomyia, a genus of small, biting midges. So, even though we are not usually in favour of midges, most of us appreciate the fruits of the Forcipomyia's labours!

Botanically, the fruit of the cocoa tree is not a pod but a berry. A berry is a fleshy fruit with one or more internal seeds, whereas pod usually refers to fruits like peas and beans. However, 'pod' is universally used in the cocoa industry. The mucilage (pulp) around the seeds (beans) is sweet, which attracts animals. They eat the pulp and the beans, digesting the former while the latter passes through their digestive tract unscathed.

Cocoa beans are rather bitter, and go through various stages of processing prior to consumption as chocolate. Cocoa pods are skillfully harvested from the tree, and the beans are removed. The beans are then fermented for up to six days, which breaks down the pulp and gives the beans their distinctive colour and flavour. After drying and grading the beans are shipped. At the chocolate factory, the beans are roasted, crushed and ground, to produce cocoa mass, cocoa powder and cocoa butter. Cocoa mass, cocoa butter, sugar and milk are then combined to produce chocolate!

The UK chocolate industry supports schemes such as Fairtrade, improving livelihoods and protecting locals from global price fluctuations. Learn more from our Fabulous Fairtrade display at the Botanic Garden (16th February to 18th March 2015).

Further reading

Coe SD and Coe MD 1996. The true history of chocolate. Thames & Hudson.

McNeil C 2006. Chocolate in Mesoamerica: a cultural history of cacao. University of Florida Press.

Thomas E et al. 2012. Present spatial diversity patterns of Theobroma cacao L. in the Neotropics reflect genetic differentiation in Pleistocene refugia followed by human-influenced dispersal. PLoS ONE 7: e47676.

Kate Castleden and Emma Williams