This essay examines how Indo-Pacific indigenous plant names went from being viewed as instruments of botanical fieldwork, to being seen primarily as currency in anthropological studies. I trace this attitude to Alexander von Humboldt, who differentiated between indigenous phytonyms with merely local relevance to be used as philological data, and universally applicable Latin plant names. This way of using indigenous plant names underwrote a chauvinistic reading of cultural difference, and was therefore especially attractive to commentators lacking acquaintance with any indigenous language or culture. When New Zealand anthropologists embraced this role for Māori phytonyms in the 1890s, however, they did so possessed of a relatively in-depth understanding of Māori culture and the Māori language. This discussion has three primary aims: to illuminate nineteenth-century scholarly engagements with Indo-Pacific plant classifications, in contrast to a prevailing historiographical emphasis on European disregard for this subject; to analyse how indigenous phytonyms acted as ‘boundary objects’ interfacing between cultures and disciplines; and to illustrate the politics of scientific disciplinarity in a colonial context.