This paper deals with a peculiar turn that the concept of "historia" underwent in the work of naturalist Carolus Linnaeus (1707-1778). In the context of traditional natural history, "historia" designated an account of all that was known about a certain stone, plant or animal. For such accounts Linnaeus provided a general structuring scheme in 1736 under the title "Methodus". Yet Linnaeus's own accounts on certain plant species deviated from the "Methodus" by containing an additional section carrying the title "historia". In this case, however, the term referred to the history of scientific activities directed towards the plant species in question. The elements of this "history" were the discovery of specimens in the wild, their transfer into botanical gardens and their exchange among gardens. It will be shown that a plant species' "history" in this sense was put together to systematically prove the unity of the species, i.e. the "subject" of a "history" in its original, broader sense. This result is used to throw new light on the transition from natural history to the history of nature during the 18th century.