The life-changing experience for James A. Duke came as he roamed the lush jungles of Panama in the mid-1960s, munching on the plants indigenous peoples used for food and medicine and learning firsthand about them.

At the time, he was two years into his job as a botanist for the Department of Agriculture and working on a federal project, ultimately abandoned, to determine the feasibility of excavating an alternative to the Panama Canal using low-level nuclear bombs.

And what he found there, and ate, excited his imagination and led him to embrace ethnobotany, a then-emerging field that investigates the healing properties of plants that indigenous peoples have used for millenniums.

His field work, incorporating botany, natural healing and anthropology, took him to remote corners of the world, often in the company of native guides and even shamans — worlds away from his early professional success as a standup-bass player in country, bluegrass and jazz bands.