Pecan

In 1879, Charles Sprague Sargent was a mere seven years into his career at the Arnold Arboretum. He had been appointed curator in 1872 and director in 1873, and by 1879, roadways and initial plantings at the Arboretum had yet to be installed. So, when Sargent was named to lead a massive forest inventory for the 1880 United States census, he had good reason to hesitate. Nonetheless, after deliberation, he agreed. Sargent recognized that the census would give him an unprecedented opportunity to visit forests across the country—in turn, strengthening the collections of the Arboretum. 

This ambitious project culminated in 1884, when Sargent published the Report on the Forests of North America (Exclusive of Mexico). In this report, Sargent aimed to describe the composition of forests across the country. Significantly, the publication included maps of the distribution of individual species and genera. These maps are considered the first attempt to render plant distributions on a large scale. Sargent travelled across the continent for the project, but given the scope of the undertaking, he needed assistants. He officially appointed botanists as “special agents,” and others provided unofficial contributions. 

One of these unofficial correspondents was Robert Ridgway, a young naturalist from Illinois. In 1880, Ridgway had been appointed the first full-time curator of birds at the United States National Museum. Although Ridgway was based in Washington, DC, he continued to study the landscape of Illinois—his home state—while he prepared a two-volume treatise on the birds of the state. His research on woodlands in southern Illinois (and adjacent portions of Indiana) far surpassed the needs of the census, and Sargent encouraged him to publish his findings “in toto.” The article ran 40 pages in the Proceedings of the United States National Museum, published in 1882. In the same year, the Arboretum received seed shipments from Ridgway, including seed for this very pecan. 

“[The pecan] is by far the largest of the hickories, being, in truth, one of the very largest of the forest,” Ridgway wrote in his report. He noted that the pecan’s “altitude and majestic appearance” was unrivaled within the forests flanking the Wabash River, the riverine border between southern Illinois and Indiana. But one of the largest specimens—175 feet high—was only measured after it had been felled, suggesting broader landscape pressures. “Originally, much the larger part of the district under consideration was heavily timbered,” Ridgway wrote. “Since the first settlement of the country, however, the distribution of the timber has very materially changed, much of the original forest having been cleared for cultivation.” 

Sargent became increasingly interested in hickory taxonomy almost three decades later. At that point, he once again wrote to Ridgway, asking for information. Ridgway responded, in 1912, with characteristically meticulous and detailed handwritten notes. “I have long been convinced that the genus is in sad need of overhauling,” he wrote, “and feel sure there are several more good species than are recognized in the books.” This pecan now stands as a testament to a long-standing botanical relationship—and to national collaboration that helped to establish the Arnold Arboretum.