Page from Carl Linnaeus’s personal interleafed copy of Materia Medica (1749), figuring the genera Urtica and Morus, both classified as Monoecia Tetrandria. C. Linnaeus, Materia Medica (Stockholm, 1749), Library of the Linnean Society (London), Linnaean Collections, Call no. BL 94, p. 149. Courtesy Linnean Society.