Twenty years ago, George R. Keiser showed that the mutilated last quire of Lincoln Cathedral, Dean and Chapter Library, MS 91 had once contained a herbal written in Middle English. He discovered moreover that passages parallel to those reconstructable for the Lincoln manuscript appear in other texts, including an important work called John Lelamour’s Herbal after a name mentioned in its explicit, and concluded that Lelamour, an otherwise unknown fourteenth-century schoolmaster from Hereford, was the author of the original treatise that Thornton and other scribes used for the composition of their own herbals. The present article will present ample evidence which will demonstrate that Keiser’s hypothesis on a Herefordian pedigree for this textual family cannot be sustained any longer, and that the origins of this textual family should in fact be sought not too far from Scotland. A linguistic approach based on a collection of scribal modifications, both unconscious and conscious ones (i. e. copy mistakes and changes made on purpose by the several copyists), will be used for the task. This will reveal how linguistic variation between the several manuscripts can be profitably used to reconstruct the dialect of the original translation, which will here consequently be named Northern Middle English Translation of Macer Floridus’s De Viribus Herbarum (or Northern Macer for short).