Although not the first publication validating the generic name Rafflesia, Robert Brown’s first classic paper on Rafflesia arnoldii was issued as a preprint in April 1821, antedating the publication of the possibly threatening name, R. titan Jack; Brown’s second paper on the genus was also first distributed as a preprint, in September 1844. New names first published in these papers are listed and remarks on the typification of Malesian species (two lectotypifications proposed) added. Rafflesia horsfieldii is apparently conspecific with R. patma, which, if proved, should prompt a move for the conservation of the later name R. patma. Precise datings for certain parts of the Proceedings and Transactions of the Linnean Society are presented and, as a result, it is necessary to propose a new combination, Thottea piperiformis (Griff.) Mabb. (Aristolochiaceae).