This paper explores some routes into the history of plant transfers, especially during the period of European imperialism. It attempts to draw on different bodies of research, which are not usually juxtaposed, and weave together perspectives from contrasting disciplines. It does not pretend to offer a history, which is a much more complex task. We have deliberately tried to include cultivated crops, garden plants, weeds and plant invaders within the same frame of analysis, because it is so difficult to define some species within any one of these culturally constructed categories. The paper develops three main points. Firstly, it raises questions about the asymmetrical pattern of plant transfers during imperialism, thus challenging some of the propositions offered in Crosby's Ecological Imperialism. Secondly, we evaluate recent literature on the history of botany and botanical institutions and suggest that a broader range of human agency needs to be considered, as well as accidental transfers, if the global trajectories of plant species are to be mapped and comprehended. And thirdly, we argue that in pursuit of generalizations about patterns of transfer, scientists have concentrated too much on plant properties, and historians on understanding political economy or institutions. A global history, as well as particular plant histories, requires a combination of insights and research from sciences, social sciences and humanities.
plant transfers; environmental history; ecological imperialism.