Title page of Andrea Cesalpino’s De plantis libri XVI, Biodiversity Heritage Library.
Andrea Cesalpino (1524-1603) is, I think, my favorite among Luca Ghini’s successors in botany because he most exemplifies the careful attention to detail and to observation that were hallmarks of his teacher’s work. He also had a philosophical side that manifested itself in his great publication De plantis libri XVI or The Plant in Fourteen Books (1583). Cesalpino had already achieved a great deal before publishing this work. He was one of Ghini’s students at Pisa, earning his degree in medicine. When Ghini left Pisa in 1555, Cesalpino took his place as professor of botany and director of the botanical garden there; he also adopted his mentor’s device for documenting plants for teaching and research: the herbarium. He created at least two, one with over seven hundred specimens which he dedicated to Bishop Alfonso Tornabuoni and which survives in the herbarium of the University of Florence. This gives a hint that herbaria were beginning to be used for a variety of purposes. While Ghini saw teaching and documenting species information as foremost, Cesalpino also saw the form as a way to thank and honor a patron.
From his correspondence and publications, which were extensive, we know that Cesalpino went on plant collecting field trips, created lists of the species growing in the Pisa botanical garden, and taught both materia medica and then general medicine. He remained at Pisa until 1592 when he became professor of medicine at the University of Rome and physician to Pope Clement VIII. This move relatively late in life was provoked by the promotion of another professor, the famous physician Girolamo Merculiale, over him at Pisa. Cesalpino remained in Rome until his death in 1605. While I’m interested here in his botanical research, he studied many areas of medicine including geology and the use of minerals as materia medica, as well as the circulation of blood through the heart, making the most progress in this area before William Harvey.
In all his work, but perhaps especially in botany, Cesalpino took a more theoretical view of natural history than was common at the time. He didn’t want to just collect information and organize it, he sought out fundamental ideas behind the details. He was Aristotelian in his approach and like Aristotle’s student Theophrastus, he attempted to formulate a system of plant classification. However, Cesalpino didn’t publish it until after he had spent many years studying plants in the field, the botanical garden, the herbarium, and the literature. Despite being a physician, he did not, like Dioscorides—then still the leading source of information about materia medica—focus on the medicinal properties of plants. Instead, Cesalpino sought basic traits on which to base his taxonomy.
Theophrastus began his system by dividing plants into four categories: trees, bushes, shrubs, and herbs, noting that the division among them is not hard and fast—a deep classificatory problem that plagues systematists to this day: living things refuse to fit into neat categories. Cesalpino used a different, but related, four-part scheme. He put trees and shrubs together; had a second category for seeds without coverings, namely gymnosperms; then came non-woody plants with covered seeds: the herbs and finally plants without discernable seeds. In a letter, he described how he would shuffle through his herbarium sheets, putting them into piles based on similar traits. This suggests that when he was working with specimens, they were not bound in volumes, but more conveniently loose for just such rearranging.
This and other interesting pieces of information are in Cristina Bellorini’s (2016) book on medicine and botany in Renaissance Tuscany, where she describes the results of Cesalpino’s studies that appeared in De plantis. Bellorini considers Cesalpino’s system as natural in that it’s based on similarities that link plants having more than arbitrary likenesses. Within his four basic categories, he groups species according to what he saw as their most fundamental functions: nutrition and reproduction. For nutrition, he looked at roots and divided them into those that became woody and those that didn’t. For reproduction, he examined flowers, fruits, and seeds. Cesalpino was not alone in focusing on such structures as key to understanding plant relationships. In an earlier post, I’ve written about Conrad Gessner’s notebooks that are filled with images and notes that often highlight just such plant parts, which Florike Egmond (2016) sees as evidence that Gessner was thinking of these traits in terms of classification.
It’s important to note that Cesalpino’s book has no illustrations. He wrote that he didn’t think they were necessary because he was less interested in differentiating among species that in illustrating ways in which they were alike. Lack of illustrations is probably one reason why he is less known today than some of Ghini’s other associates such as Pietro Andrea Mattioli, whom I’ll discuss in the next post. In many cases images in publications made them more popular and therefore more likely to be republished. In the present day, early botanical works are often valued for their illustrations rather than for their texts, which is definitely the case with Mattioli.
In his history of botany, A.G. Morton (1981) regards Cesalpino’s contributions to the development of plant classification very highly. He presents Cesalpino’s work in detail relative to how he treats many other botanists’ thought. Morton sees Cesalpino as one of the few botanists before the 17th century to deal with fundamental questions about how to organize plant knowledge. Obviously this issue became more urgent as more and more species became known, but even in the 16th century, plants from the Americas and Asia were being grown in Pisa. For example, Cesalpino discusses the tomato, sunflower, and agave. He seemed to understand the way botany was heading and felt it necessary to think deeply about plant organization. He followed in the tradition of his teacher, Luca Ghini, in amassing specimens and information, and then subjecting it all to careful analysis.
References
Bellorini, C. (2016). The World of Plants in Renaissance Tuscany. Surrey, UK: Ashgate.
Egmond, F. (2016). Eye for Detail: Images of Plants and Animals in Art and Science, 1500-1630. Chicago, IL: University of Chicago Press.
Morton, A. G. (1981). History of Botanical Science. New York, NY: Academic Press.
Herbarium World 