Throughout the late 1840s and the early 1850s, Harvard botanist Asa Gray and his close friend George Engelmann of St. Louis engaged themselves with recruiting men who sought to make a living by natural history collecting, sending these men into the field, searching for institutions and individuals who would subscribe to incoming collections, compiling catalogs, and collecting subscription fees. Although several botanists have noted Gray and Engelmann’s bold experiment as having introduced America to a mode by which European naturalists had (...) devised to organize scientific expeditions, historians of science have not taken the “subscription mode” seriously. I argue that it was specifically by undertaking the labor of cataloging species and charging subscription fees for the cataloged species that Gray established himself as a metropolitan botanist. One crucial consequence of Gray’s rising profile was that he acquired sufficient “cataloging power” to secure his status as an authoritative cataloger of species, and as a kind of “mint” or “storehouse” :1–28, 2001a) who produced well-pruned lists of American species to enable transactions between American and European botanists. But this essay is not focused on the Europeanization of American taxonomy. Drawing on work by scholars who place emphasis on how new forms of knowledge get produced when knowledge travels, my focus here is the evolution of the subscription mode when Gray and Engelmann adapted it to American natural history. My conclusion examines what historian of science Vanessa Heggie :318–334, 2014) identifies as the “danger of category dominance” in today’s historiography of science and shows how a kind of “assemblage thinking” may help historians cope with this danger. (shrink)