[1] It was organized by Henry Hurd Rusby, who at age 64, was a well known explorer, a professor at Columbia University, and a staff member at the New York Botanical Garden.
He hired Orland Emile White, a staff member at the Brooklyn Botanic Garden, to assist with collection and handling of plant specimens.
Rusby was forced to leave the expedition due to neuritis, an infected tooth, and his age; however, White and Martín Cárdenas continued to collect.
News from 1921: Members of the expedition left La Paz, Bolivia, about July 9, whence they proceeded by rail to Eucalyptus, the terminus of the railroad.
In December, Rusby was forced to leave the expedition due to ill health, traveling alone down the river until he was rescued by a government patrol boat.