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2 Cacao and Its Relatives in South America An Overview of Taxonomy, Ecology, Biogeography, Chemistry, and Ethnobotany Nathaniel Bletter and Douglas C. Daly Cacao belongs to an almost exclusively South American group of about forty species of small trees in the closely related genera Theobroma and Herrania. Along with the rest of the family Sterculiaceae, these genera have recently been subsumed into the larger Malvaceae family (Soltis et al. 2000), along with the common garden hibiscus (Hibiscus species), the marsh mallow (Althaea officinalis L.), the linden tree (Tilia americana L.), and the durian fruit of Southeast Asia (Durio zibethinus Rumph. ex Murray). Although some who know the durian and its reputable smell might now swear never to come near a cacao fruit again, the pulp of the cacao tree fruit is quite delicious, and it is enjoyed throughout South America today as it has been in the past. It is enlightening to look at the taxonomy of all the species of Theobroma and Herrania used by people in South America, the center of diversity for both these genera, because by examining these relationships we can appreciate their diverse ecology, chemistry, and ethnobotany, including their medicinal, edible, and psychoactive uses. Taxonomy In the past, some taxonomists considered Herrania and Theobroma synonymous , but today the genera are considered distinct (see, for example, Whitlock and Baum 1999). Strange as it may seem for such scientifically interesting and economically important plants, it has been more than 40 years since the taxonomy of the two genera was comprehensively revised (Cuatrecasas, 1964; Schultes 1958). Some sixty-eight names have been published in Theobroma and twenty-three in Herrania (six of the latter with synonyms in Theobroma), but current practice recognizes twenty species in Theobroma, one of these with three varieties, and seventeen in Herrania (Laurence J. Dorr, personal communica- Nathaniel Bletter and Douglas C. Daly 32 tion 2004). A number of formae, or forms (an archaic taxonomic rank below species and variety that represents minor morphological variants) were published in both genera, but forms are rarely recognized in modern taxonomy. Both genera traditionally have been placed along with another famous stimulant , cola nut (Cola nitida [Vent.] Schott & Endl.), in the family Sterculiaceae, but reorganization of this sector of the flowering plants based on molecular systematic studies is tending to group Sterculiaceae and various of its former “neighbors,” including Malvaceae, Bombacaceae, and Tiliaceae, into a single family, the Malvaceae, although still within the order Malvales. The traditional Bombacaceae also includes plants with large pods containing edible seeds, such as the provision tree (Pachira aquatica Aubl.), the durian fruit (D. zibethinus), the kapok tree (Ceiba pentandra L.), and the baobab (Adansonia digitalis L.), as well as Quararibea funebris (La Llave) Vischer, whose flowers are often mixed into cacao beverages in Mexico. The close relationship between Theobroma and Herrania has been recognized by traditional peoples, as evidenced by the fact that the folk generic, the grouping in a compound common name, is usually the same; an example is the Amazonian species Herrania mariae (Mart.) Decne. ex Goudot (see Figure 2.1), called cacau de jacaré or “cayman’s cacao” where it occurs in Brazil, presumably because of its rough exterior. Herrania is distinguished from Theobroma by the former’s palmately compound (vs. simple) leaves, the calyx usually three-lobed (vs. usually five-lobed), and the appendage on the end of the petals many times (vs. only two to three times) longer than the basal part and coiled (vs. reflexed or erect) in bud; in addition, the fruits of Herrania tend to be more conspicuously ribbed and have a drier husk, but this is not diagnostic (Schultes 1958). The relatively widespread Theobroma bicolor Bonpl. (Figure 2.2), known as pataxte or balamte in Mesoamerica, macambo in Peru and Colombia, and cacau do Peru in Brazil, is another of the more important relatives of cacao. It was considered by Cook (1915, 1916) to represent a third genus, Tribroma, based on differences between it and T. cacao L. in its architecture, leaf venation, inflorescence structure, flower morphology, and pericarp (fruit husk), but this name is not in use. Theobroma bicolor has palmately veined leaves, inflorescences with finite branching on new branches, red flowers with thick club-shaped staminodes (sterile stamens), and a woody pericarp; T. cacao has mostly pinnately veined leaves, indeterminately branched inflorescences that are produced adventitiously on the trunk or older branches, pale flowers with pink nectar guides and slender pointed staminodes, and a more fleshy pericarp. Subsequent examination showed that...

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