At the beginning of the 21st century, knowledge systems about nature face severe challenges. While science is heralded as a key contributor to future solutions of environmental problems, it is also investigated as a cause of nature’s destruction. In order to better understand the position and potential of scientific knowledge in the present crisis, there is a new need to examine the foundation period of natural science, its historical context and inherited structures. This project contributes to a wider debate on the development of scientific knowledge and environmental consciousness in the second half of the nineteenth century through a rigorous archival-based historical case study that examines the role of gender, locality and subjectivity in the transnational making of knowledge about nature. Mary Elizabeth Barber (1818-1899) was an exceptional British born and South African-based naturalist. In her pursuit of Humboldtian science, she transgressed gender boundaries, borders between the colony and the metropolis, and between local and cosmopolitan knowledge networks.