ABSTRACT In the early decades of the twentieth century, the Smithsonian Institution, in collaboration with other partners in the US scientific establishment, sought on multiple occasions to oversee the preparation of a Philippine flora. Boosters originally conceived of the project in 1903 as a means of showcasing US colonial prowess and aiding the economic and cultural development of the Philippines as part of a benevolent civilizing mission. By the 1920s, however, the justification for the Philippine flora increasingly emphasized the US-Filipino partnership, although US officials immediately undercut this collaborative rationale by suggesting that Philippine institutions lacked the skill and infrastructure to preserve and care for specimen collections. This account of how visions of nation-building and imperial power shaped the Smithsonian’s quest for a Philippine flora contributes to ongoing scholarly efforts to integrate the United States into the global history of botany and empire.