The tree, Theobroma cacao, provides the source material for what eventually becomes chocolate. Pods containing seeds (commonly referred to as cocoa beans) grow off the trunk of the tree.
The tree itself thrives in the understory of the rainforest canopy, requires adequate precipitation (2.5 – 5 cm per week), takes approximately six months post-fertilization to produce mature pods (i.e. fruits) and yields fruit year-round. Described as a tropical to subtropical species, chocolate (and therefore some would also say money) does indeed grow on trees, specifically in the raw form of pods. The species, Theobroma cacao L., gets commonly referred to as the cacao tree or the chocolate tree.
Pollination depends primarily on a species-specific relationship with a small fly called a midge (classified with the Family Ceratopogonidae and within the genus Forcipomyia) that lives in the discarded leaf litter layer of the soil.
Theobroma cacao exhibits a lot of phenotypic variation (i.e. differences in appearance) within pod shape, texture and color. Described as a tropical to subtropical species, Theobroma cacao L.
Theobroma cacao grows generally within twenty degrees latitude of the equatorial belt all across the world. Height of the trees vary with cultivation practices. Cacao farmers favor lateral spread of the branches and tree heights of 6-12 m (20 – 40 ft) to increase accessibility to the pods which grow directly off the trunk of the tree (i.e. a botanical trait called cauliflory). Wild non-domesticated cacao can reach heights of over 20 m (> 65 ft).
Naming provenance
The genus, Theobroma, translates from Greek into “food of the gods.” This translation applies in a contemporary sense of considering chocolate as a major food group. However, the translation falls short of characterizing the commonly accepted major manner of consumption of chocolate as a beverage during pre-Columbian times.
The species, T. cacao, represents the single species from which we derive chocolate. In biological terms, T. cacao warrants its own designation of a species based on the classical view of the Biological Species Concept (BSC).
One of many, the BSC classifies a species based on the premise of reproductive isolation through the inability of individuals from one species to produce a viable offspring with individuals from another species. Subsequent genetic sequencing of the cacao tree supports this classification but also indicates considerable variation within the species resulting in what we term genetic subspecies, varieties or clusters.
In 1735, Swedish botanist Carolus Linnaeus, the father of modern nomenclature in biology, founded the naming system for recognizable species where the genus represents those most closely related and the species represents individuals with unique traits.
The capital and italicized “L.” following the genus (Theobroma) and species (cacao) refers to Linnaeus who named the cacao tree in 1753. Although T. cacao’s origins point to the Amazonian basin, Linnaeus used specimens from collections of the British Museum Founder, doctor and botanist Sir Hans Sloan to describe the cacao tree.
These collections took place primarily in Jamaica where Sir Hans Sloan and his wife held extensive land holdings and owned acres of plantations where heinous acts of abuse and slavery took place. The British Museum digitized all of the specimens (an open access source) from Sloan’s collection across the West Indies.
Cacao bean or seed
A certain amount of semantic confusion surrounds the term “cacao bean” versus a seed.
In botanical terms, T. cacao produces seeds, not beans. However, most people refer to cacao pods that contain beans. Cacao trees produce pods, which do not show dehiscence, or the self-splitting of a plant structure, that one sees in true beans such as peas or flowers such as milkweed. If biologically a true bean, then cacao would belong to the larger family of Fabaceae (19,000 species) instead of Malvaceae, a smaller family which includes over four thousand plants with edible seeds.
For cacao, each pod contains several individual seeds surrounded by their own fleshy pulp. Each cacao pod contains a range (~20-60) of seeds depending on the characteristics of individual trees. The mucilaginous sweet pulp surrounds the seeds as well as the placenta, a structure from which the seeds gain nourishment. After splitting open the pod, cacao farmers strip the pulp-covered seeds/beans off of the placenta.
Evolutionary history
Only T. cacao produces the beans that get transformed into what we typically recognize as chocolate. The genus Theobroma contains over twenty different species. Theobroma cacao branched out into its own species approximately 10 million years ago.
Two other closely related species, T. grandiflorum (commonly called cupuaçu, also spelled cupuassu, cupuazú, cupu assu, or copoazu) and T. bicolor (also known as Jaguar Cacao, Patashte, Balamte, or Macambo) also produce beans that some makers transform into a product that may look similar to chocolate but does indeed taste different.
Other makers use the fruits or seeds from other Theobroma spp. as inclusions in chocolate made from T. cacao.
How to refer to the chocolate tree
To write a scientific name properly to refer to a single species, one should always capitalize the genus and never the species, but italicize or underline both (e.g., Theobroma cacao). One can then subsequently abbreviate a genus with capitalization of the first letter followed by a period (e.g., T. cacao), except at the beginning of a sentence in which one should write out the name in full.
The use of “sp.” after a genus refers to an unnamed single species while “spp.” means several species within that genus. For example, future researchers may discover a new Theobroma sp. As they explore more of the deep Amazon as we know several different fruits come from Theobroma spp.
Próximamente versión en español
Entry added: May 28, 2023; Entry updated: September 21, 2023
Verified on: September 23, 2023
Authored by
Romi Burks, Professor of Biology
Educator
References
The Chocolate Tree: A Natural History of Cacao. Allen M. Young, University Press of Florida, 2007.
“From Cacao to Chocolate,” Mary Alice Koeneke, PennState Extension, January 20, 2023.
“Specimens,” Natural History Museum, Accessed on June 2, 2023.
“The age of chocolate: a diversification history of Theobroma and Malvaceae,” James E. Richardson, Barbara A. Whitlock, Alan W. Meerow and Santiago Madriñán, Front. Ecol. Evol. November 10, 2015.
Have a comment on this definition?