We aimed at building a dataset of preserved specimen records of cacao and its wild relatives (genera Theobroma and Herrania), with a particular strength in Tropical Americas, where both genera are native to, but eventually also comprising records overseas. This dataset includes revisited data only of preserved specimen collections (i.e. data deposited in herbaria) and should enable downstream works with systematics, conservation and evolution of a Neotropical group of relevance in Tropical Americas.

Our dataset was first obtained from the GBIF database, downloaded on 3 August 2020 (GBIF.org 2020). This initial dataset has 15849 entries from 313 datasets, including thirteen entries of fossil specimens, 919 entries of human observations, 287 entries of living specimens, 28 entries of machine observations, 81 entries of material samples (e.g. records from spirit collections), 11305 entries from preserved specimen collections (i.e. materials found at herbaria) and 3216 entries of unknown precedence. It should be noted that, for the purposes of this study, only preserved specimen collections were considered, because these can be reached at herbarium collections and be properly attested with respect to their geographic origin and taxonomic identity. For these, herbarium acronyms for preserved specimen collections followed Thiers (2021) designations.

The downloaded dataset (GBIF.org 2020) was the gold-standard source for an extensive taxonomic revision conducted by the authors of this study. This revision included both field expeditions, as well as the study of the preserved specimen materials, morphological and phylogenetic analyses which will ultimately derive in the publication of a new, updated taxonomic revision for the taxa being studied in here. After data manipulation, data cleaning and checking coordinates and the precedence of the vouchers, we kept 7975 preserved specimen records for 32 species in two genera. GBIF-mobilised data are available as Supplementary Material (Suppl. material 1).

1760-1-01 - 2020-8-03.

By the time of this analysis, periods of collection peaks are observed in 2014, with 491 new entries in a single year, followed by 1992, with 252 new entries and then by several years from 70s to 90s (Fig. 7).

The history of cacao collecting expeditions is marked by numerous expeditions led by American or European botanists, in contrast with a few led by Latin American teams. Consequently, most preserved specimens are found at American or European herbaria, especially at MO, NY, US, F, U, L and K collections.

Below, we describe a chronological sketch of the most relevant moments where wild cacao species collections were made over the last centuries, according to our dataset and considering the chronology summarised in Fig. 7.*1

ca. 1689

The epoque of the first known record used as type of a name of Theobroma, collected by Sir Hans Sloane (1660-1753), a British physician and naturalist who travelled to the Caribbean, where he documented his travels and collected the first specimen of Theobroma cacao L. from Jamaica, which was later assigned as the lectotype of Theobroma cacao L. by Cuatrecasas (1964). The specimen can be found at the London Natural History Museum (BM). Sir Sloane made one of the first descriptions of a popular use of a Theobroma, where he was credited as being the first to report the use of T. cacao as a bitter drink (Delbourgo 2011).

1775

First dated collection made of Theobroma with known location and collector. This specimen was collected by Jean Baptiste Aublet (1720-1778), a French botanist who worked with the French Guiana flora. This collection, first labelled as “Cacao guianensis Aubl.”, the type of its name, is originally ascribed to the surroundings Cayenne and it is actually a Theobroma speciosum Mart. The material is deposited at the Natural History Museum (BM).

1777-1778

The Spanish botanists Hipólito López (1754-1816) and José Pavón y Jiménez (1754-1840) and the French naturalist Joseph Dombey (1742-1794) led the Botanical Expedition to the Viceroyalty of Peru, collecting more than 3,000 botanical samples deposited mostly in the Royal Botanical Garden of Madrid (MA), with duplicates sent to the Field Museum (F) and to the Missouri Botanical Garden (MO). This expedition culminated in the production of ten volumes of the Flora Peruviana et Chilensis prodromus (see Steele (1964)). The type series of Theobroma sinuosum Pav. ex Huber are some of the important collections from these samples.

1787-1803

Accomplishment of “The Spanish Royal Botanical Expedition to New Spain” (Plantae Novae Hispaniae), also known as the “[Martín de] Sessé & [José Mariano] Mociño Expedition”, led by many botanists familiar with works of Linnaeus and Nilokaus Jacquin. The expedition was carried out in the actual region of Mexico, Guatemala, Nicaragua, Cuba and Porto Rico reaching the north-western US, with an estimated number of plant collections varying between 8,000-10,000 (McVaugh 2000). Specimens of T. bicolor (labelled as Theobroma ovatifolia Sessé & Mociño, a name not validly published) and T. cacao, found cultivated in the area, as well as T. angustifolium were collected. Most of these collections are deposited in American herbaria, such as the Field Museum (F) and the Missouri Botanical Garden (MO).

1825-1830

William Burchell (1781-1863), an English naturalist, travelled to Brazil collecting a large amount of plants, but especially insects. Such expedition culminated in the publication of Catalogus Geographics Plantarum Brasiliae Tropicae. Records of T. subincanum and T. grandiflorum are part of Burchell’s collections, which can be found in London, at the Royal Botanic Gardens, Kew (K).

1830

First known collection of Herrania made by Eduard F. Poeppig (1798-1868), a German botanist who worked as a naturalist in Cuba and made expeditions in Chile, Peru and Brazil, publishing Reise in Chile, Peru und dem Amazonenstrome, während der Jahre 1827-1832. Collections of Herrania nitida (Poepp.) R.E.Schult., are from this time. Poeppig’s collections of Theobroma are deposited at the Naturalis Biodiversity Center (L, U and WAG collections), Field Museum (F) and at the Natural History Museum of Vienna (W).

1843-1846

Justin Goudot (1802-1850), a French naturalist, made field expeditions in Colombia, where he collected many species of vertebrates (Palmer 1918), but also plants, such as H. albiflora, H. laciniifolia and H. pulcherrima, which comprise the first dated records for these species as well as records that formed the basis for the creation of the genus Herrania. Goudot’s duplicates of Herrania are deposited at the French National Herbarium (P), Geneva Herbarium (G) and at the Field Museum (F).

1851

Richard Spruce (1817-1893), a British botanist, made his first collections of Theobroma from this time, with records of T. sylvestre, T. grandiflorum and T. speciosum. These specimens are samples from his journey to Amazonia (dated mostly from 1849 to 1864), starting from the Andes up to the upper Amazon River, collecting in Brazil, Ecuador and Peru (Seaward 2000, Pearson 2004). Most of Spruce’s collections can be found at the Royal Botanic Gardens, Kew (K) and in the New York Botanical Garden (NY).

1858

Paul Sagot (1821-1888), a French botanist who collected in Guiana, making new collections of Theobroma in the area. Sagot’s collections are deposited at the French National Herbarium (P) and at the Royal Botanic Gardens, Kew (K).

1874-1875

James Trail (1851-1919), a Scottish botanist, made expeditions in the Upper Amazon and tributaries, including northern Brazil, where he made collections of Theobroma. Trail’s collections are deposited at Royal Botanic Gardens, Kew (K) and at the French National Herbarium (P).

1880

Auguste Glaziou (1829-1906), a French botanist, collected in Brazil between 1861 and 1895, making collections of Theobroma, which can be found at the French National Herbarium (P).

1891-1911

Henry Pittier (1857-1950), a Swiss botanist, explored areas of Panama, Colombia and Venezuela (Dwyer 1973), making several collections of forested areas in these countries, publishing Primitae Florae Costaricensis and Herborisations au Costa Rica and depositing most materials at the Smithsonian National Herbarium (US), French National Herbarium (P), Field Museum (F), Royal Botanic Gardens, Kew (K) and at the National Museum of Costa Rica (CR).

1904-1969

Adolpho Ducke (1876-1959), an Austrian botanist naturalised in Brazil, made several collections in the Brazilian Amazon, where he studied many plants and published several works for the area, including with Theobroma (Ducke 1940). Most of Ducke's collections can be found at the Emilio Goeldi Museum in Belém, Brazil (MG).

1905-1919

Auguste Chevalier (1873-1956), a French botanist, made new collections of Theobroma species, especially T. cacao from Africa, where he studied T. cacao morphotypes and cacao cultivar classification.

1914

Orator Cook (1867-1949) and Conrad Doyle (1884-1973), both American botanists from the Smithsonian Institution (US), led expeditions in Mexico, Colombia, Costa Rica and Guatemala, where they identified stilt palms and collected, amongst other species, cacaos from Guatemala.

1903-1910

A team of Dutch botanists arrived in Suriname, collecting specimens of Herrania from the area which, after World War II, were all sent to the Naturalis Biodiversity Center collection of Utrecht (U) (Klooster et al. 2003).

1906-1929

Walter Broadway (1863-1935), an English naturalist, served as gardener in the Royal Botanic Gardens (K) and later as superintendent in Trinidad, where he made Theobroma collections also in French Guiana and Venezuela. Most of his duplicates are found in BM, K, MO and P.

1929-1942

Llewelyn Williams (1901-1980), an English botanist who was interested in botanical products from tropical regions, conducted extensive field expeditions in northern South America, following the margins of the Orinoco River Basins. Most of his collections are deposited at the Field Museum (F).

1916-1948

Ellsworth Killip (1890-1968) and Albert Smith (1906-1999), American botanists from the Smithsonian Institution (MO), collected extensively in Colombia, Brazil, Cuba, Jamaica, Panama, Peru and Venezuela, where they had the opportunity to collect wild cacao species from these areas. Duplicates were mostly sent to MO, F and US.

1920-1933

Guillermo Klug (-1946), a Peruvian parabotanist, made extensive collections in Amazonian Peru and Colombia, contributing with the knowledge of wild cacao species and other elements of the flora of the area. Most of its specimens and notes were sent to US herbaria, with duplicates at F and NY.

1928-1950

Boris A. Krukoff (1898-1983), a Russian botanist, led numerous expeditions in Amazonia, collecting wild cacao species mostly between 1931 and 1939 in the Basin of Rio Solimões in Brazil.

1938-1945

Frederick J. Pound (1919-1944), a British biologist from the Imperial College Station of London, established the first cacao germplasm collection, leading expeditions in Upper Amazonia, in Rio Ucayali, Rio Morona and Rio Marañón in Peru and Ecuador (Zhang et al. 2009) to find new cultivars of cacao, collecting pods from trees. Most specimens were not deposited in herbaria and are kept only as germplasm.

1939-1969

José Cuatrecasas (1903-1996), a Spanish botanist from the Jardim Botánico de Madrid (MA), conducted extensive trips in South America, collecting in Colombia, Venezuela and Ecuador. Cuatrecasas spent years of his life studying plants, with a particular focus in the genus Theobroma, describing new species and publishing the seminal taxonomic revision of the genus (Cuatrecasas 1964). Most of Cuatrecasas’s collections are found at the Smithsonian Institution (US).

1942-1960

Richard E. Schultes (1915-2001), an American ethnobotanist from Harvard University, led expeditions in South America and Mexico, mostly looking for useful plants used by indigenous people. During this time, he also became interested in the wild cacao species, especially those of the genus Herrania. His interest and fieldwork resulted in the publication of Herrania’s synopsis (Schultes 1958), a gold standard for the taxonomy of the genus. Most of his collections are found in American herbaria, namely US, F, GH and MO.

1942

William Archer (1894-1973), an American economic botanist from the Smithsonian Institution (US), carried out expeditions in Pará, Brazil, where he collected many samples of Theobroma. Most of the duplicates were sent to US and F.

1945-1946

Ricardo Fróes (1891-1960), a Brazilian botanist associated to the Instituto Agronômico do Norte, in Belém do Pará, led expeditions in the region of Fonte Bôa, Amazonas, Brazil, from where some collections of Theobroma are derived.

1953-1967

Elbert Luther Little, Jr. (1907-2004) and Ruby Rema Little (1907-2009), both American botanists, collected in Venezuela and Costa Rica. Most duplicates of these expeditions can be found at F.

1951-1963

Victor Patiño (1912-2001), a Colombian botanist, led expeditions in Andean countries (Venezuela, Colombia, Peru, Ecuador, Bolivia and Chile), depositing most of his samples at Medellín Germplasm Bank with duplicates sent to F and US collections.

1952-1953

Period of the Anglo-Colombian Cacao Collecting Expedition. With expeditions led by the American botanists in collaboration with the Imperial College of Tropical Agriculture of Trinidad and the Colombian Government, the areas explored included the rivers Caquetá, Apaporis, Vaupés, Negro and tributaries towards Putumayo and El Chocó (Baker et al. 1953), collecting almost 200 botanical samples, mostly of T. cacao, but other species of Theobroma and Herrania. The Anglo-Colombian Cacao Collecting Expedition counted with the interaction of Schultes and Cuatrecasas. Many specimens from these expeditions are found in American collections, especially F and US, but also at COL in Bogotá, Colombia.

1963-1975

Roelof Oldeman (1937-), a Dutch botanist from the Natural History Museum (BM), made several trips to the Guianas and northern Brazil, collecting samples of Theobroma and Herrania. Most of its wild cacao species collections can be found at U, US and P.

1965-1966

Basett Maguire (1904-1991), an American botanist from the New York Botanical Garden (NY), led an expedition to the Serra da Neblina Expedition, collecting in the region of Rio Negro and Rio Cauaburí, in Brazil. This expedition was conducted by the University of Brasilia in conjunction with the Instituto Nacional de Pesquisas da Amazonia (INPA) and the New York Botanical Garden (NY), with funds from the National Science Foundation. Maguire's collections from that time can be found at INPA and NY.

1964-1989

Ghillean T. Prance (1937-), an English botanist, led the Projeto Flora Amazônica, an initiative funded by the Brazilian Government and the National Science Foundation, aiming at collecting in particular areas of the Brazilian Amazonia. Collections from this project include Theobroma and Herrania and are mainly found at INPA, US and NY.

1968-1972

Thomas Croat (1938-), an American botanist interested in systematics and ecology of Araceae, made expeditions in the region of Loreto, in Peru, where he collected samples of wild Theobroma and Herrania species, mostly deposited at F, MO and NY.

1969-2005

José Schunke-Vigo (1929-2018), a Peruvian botanist, collected Theobroma and Herrania especially in the Peruvian Amazonia, contributing greatly with the Flora of Peru (Croat and Graham 2019). Most of his specimens were deposited at F and US.

1971-1991

Paul Maas (1939-), a Dutch botanist from Urecht University (U), carried out expeditions in the Guianas and in Ecuador to publish floristic treatments for these regions, where he also collected Theobroma and Herrania. Maas travelled to over twenty countries, often visiting each place more than once and he was mostly accompanied by other colleagues and students on his trips (Koek-Noorman 2004).

1973-1983

Ronald Liesner (1944-), an American Botanist from the Missouri Botanical Garden (MO), made expeditions in the region of Costa Rica and Panama, collecting samples of Theobroma and Herrania purpurea, with most materials found at MO.

1976-1986

Juan Revilla, a Peruvian botanist working in the Instituto Nacional de Pesquisas da Amazônia (INPA), Brazil, led expeditions in Peru, mostly under the auspices of the Flora do Peru project, in collaboration with the Missouri Botanical Garden (MO) and the Field Museum (F), funded by the National Science Foundation. Most of Revilla's collections can be found at F, INPA and MO.

1974-1997

Scott Mori (1941-2020), an American botanist from the New York Botanical Garden (NY), coordinated expeditions in several sites of Brazil and Suriname, the latter supported by the Fund for Neotropical Plant Research. Most of Mori's Theobroma and Herrania samples were sent to American collections of US and NY.

1976-1978

The Project “Plantas da Amazônia”, also funded by the National Science Foundation in conjunction with Brazilian Government, explored areas Brazil’s Amapá State, with most Theobroma and Herrnia samples found at MO, F and US.

1980-1986

Carlos D. Cid-Ferreira, a Brazilian botanist, based at the Instituto Nacional de Pesquisas da Amazonia, led several expeditions to different areas of Amazonia, including Acre, Rondônia, Pará and Amazonas States, reaching newly-collected areas. Many vouchers of Theobroma and Herrania collected in this occasion were deposited at INPA and duplicates were sent to American collections.

1989-1999

Marion Jansen-Jacobs (1944-), a Dutch botanist, made expeditions in the Guianas, in association with the Utrecht University (U), where most of his samples of Theobroma and Herrania species can be found.

2000-onwards

Collections of different authors prevailed from that time and focused expeditions became less recurrent. In fact, many of the recent expeditions are characterised by revisiting recollected spots. One exception is the Colombian Expedition "Cacao BIO" conducted in 2020, where more than 5000 samples and 200 samples of wild cacao species were collected in many parts of Colombia. This expedition was coordinated by the Corporación Colombiana de Investigación Agropecuaria - AGROSAVIA and the dataset is avaialble in GBIF (González-Orozco et al. 2021). Although our study did not consider the dataset from Cacao BIO, because the entries did not consist of preserved specimen occurrences, Cacao BIO is a remarkable expedition in terms of newly-collected samples and one of the largest made so far, at least for Tropical Americas, in terms of biological sampling.

Four botanical expeditions are relevant to the increase of wild cacao species collections, as described in Fig. 3: (1) the Anglo-Colombian Cacao Expedition collection, (2) expeditions made by José Cuatrecasas and (3) Richard E. Schultes and (4) Boris A. Krukoff collections in Brazil.

Other