Since Alexander von Humboldt’s training was in geology and Aimé Bonpland’s in botany, it’s not surprising that Bonpland took the lead in plant collecting on their Latin American expedition (see last post). However, because they were essentially on their own, picking up assistants along the way, their work in processing specimens, in taking meteorological and astronomical readings, etc., was usually a team effort. They were overwhelmed by the exciting new plants they saw and within the first few months had already amassed 4000 specimens. They had to order more paper, since they were using it up so quickly. It is impossible to say how many plants they collected in total, but the number is over 60,000 including 6,000 species, over half of them new (Lack, 2009). None of these numbers are precise because many of the plants passed through several different hands, but the record is clearer than for many collections of the era because the two kept careful records that became a model for later expeditions. They numbered each specimen and recorded it in a journal along with a tentative ID, a description, and locality information. As time went on, the entries became more detailed. While they sent back a number of shipments divided among several ships to guard against loss, they kept a small herbarium with them as a memory aid for what they had seen.
Needless to say, none of this work was easy. Humboldt and Bonpland were traveling through rough, often mountainous terrain in hot and humid equatorial regions where they were driven mad by insects. These conditions damaged or destroyed many of their specimens, and at one point they were so discouraged by the losses that they made to nature prints to document the plants. Over 200 of these are preserved at the Institut de France in Paris (Lack, 2001). However, they persisted in collecting because they just couldn’t ignore all the new species they encountered. Through much of their trip they were in areas that the eyes of trained botanists had never seen so they were inundated with novelty. Along with all the environmental data they had amassed, this treasure trove made them anxious to return to Europe and begin writing up their findings. After leaving South America, they spent a year in Mexico, then returned to Cuba to pack up their specimens for shipment to Paris. Humboldt decided to live there rather than to return to his native Prussia, because Paris was an intellectually alive city at the time with the National Museum of Natural History (MNHN) as the center of the country’s botanical research. There was a great herbarium there, as well as a botanical library and experts to assist them.
Humboldt and Bonpland organized and divided up the collection so they each had a set of specimens. Humboldt arranged for Bonpland to receive a pension from the French government to support him. Bonpland became botanist to the Empress Joséphine at Malmaison estate, where he oversaw the gardens, provided her with new exotics, and saw to the lavish publications on her plant collection. It soon became obvious to Humboldt that even with frequent nudging, Bonpland wasn’t getting anywhere with describing their plants. So in 1813, eight years after they returned, Humboldt invited Carl Kunth, a young German botanist, to come to Paris and work on the collection. Kunth remained for over six years and eventually published seven volumes with descriptions of over 4,500 plant species, among which 3,600 were new to science (Lack, 2009). However, this summary makes the process seem more clear cut than it was.
In 1814, Empress Joséphine died, and Bonpland decided to return to South America; he felt more comfortable exploring for new plants. He took his herbarium with him, and perhaps more importantly, he packed the botanical journals where the specimens were catalogued. Humboldt and Kunth were aghast, and Kunth hurried to the port of Le Havre to intercept Bonpland before his ship sailed. Bonpland didn’t give up his specimens, after all Humboldt had a collection too, but he did return the notebooks to Kunth, making it possible for the latter to continue his taxonomic work (Lack, 2004). Eventually, Bonpland returned his sheets to the herbarium at the MNHN in Paris, where they were filed in the general collection rather than kept separately as the Humboldt collection is.
Another wrinkle was that, while still in South America, Humboldt had sent specimens and seeds to his mentor Carl Willdenow, who wrote descriptions of a number of species. Some of these were published by others after Willdenow’s death, and his herbarium was sold by his heirs to the Berlin herbarium. Because of the hostility between France and German, Berlin botanists refused to share specimens with Kunth, who then named some of the same plants, causing years of nomenclatural difficulties. Kunth returned to Germany after completing most of his work for Humboldt, and when he died his herbarium was also sold to the Berlin-Dahlem Botanical Garden. During World War II, the Willdenow specimens were considered valuable enough to be stored in a vault offsite and survived the bombing that destroyed most of the herbarium’s collection, including the Kunth specimens. Lest you assume that by now all of the Humboldt-Bonpland plants had been identified, that may not be the case. In 2007, a new species, Solanum humboldtianum, was described from a relatively recent collection, but researchers discovered that Humboldt and Bonpland had collected it, and it had lain unidentified for two centuries (Granados-Tochoy et al., 2007). This is all fodder to feed my love of herbaria.
Granados-Tochoy, J. C., Knapp, S., & Orozco, C. I. (2007). Solanum humboldtianum (Solanaceae): An endangered new species from Colombia rediscovered 200 years after its first collection. Systematic Botany, 32(1), 200–207.
Lack, H. W. (2001). The plant self impressions prepared by Humboldt and Bonpland in tropical America. Curtis’s Botanical Magazine, 18(4), 218–229.
Lack, H. W. (2004). The botanical field notes prepared by Humboldt and Bonpland in tropical America. Taxon, 53(2), 501–510.
Lack, H. W. (2009). Alexander von Humboldt and the Botanical Exploration of the Americas. New York, NY: Prestel.