“Watson's major botanical endeavour was producing several versions of a work first entitled Outlines of the Geographical Distribution of British Plants (1832); it reached its most extensive form as Cybele Britannica, or, British Plants, and their Geographical Relations (4 vols., 1847–59). Volume four contains his most detailed phytogeographical conclusions. After publishing several supplements, he summarized his data in Topographical Botany: being Local and Personal Records towards shewing the Distribution of British Plants (2 vols., 1873–4). He was working on a second edition of it when he died; it was completed by John G. Baker and William W. Newbould (1883)” (ODNB).

Digital facsimile of the 1832 edition from the Hathi Trust at this link.