In Volume 4 of the Papers of the Michigan Academy, Frank C. Gates and John H. Ehlers (1925) presented an annotated list of the higher plants found in the two-county region around the University of Michigan Biological Station, at the northern end of the Lower Peninsula of Michigan. Supplements were published in 1928, 1931, and 1948. The Gates and Ehlers list became widely known and frequently cited, for there are relatively few such accounts of floristics in the northern Great Lakes region. Before a completely new list can be prepared it seems desirable to continue to keep the work of Gates and Ehlers up to date. The previous lists were based almost entirely on the work done at the Biological Station and did not attempt to present a comprehensive report on the regional flora derived from earlier work of others as represented in the literature or in herbaria. Seldom, even, were citations of their own collections in monographic works listed by Gates and Ehlers when these would have been additions to the regional flora. In working toward a new list, I have attempted to account for all previously published records for the region and to study relevant herbarium material (so that no species is admitted to the list unless I have examined an actual herbarium specimen). The present list of additions, therefore, includes a considerable share of older records besides those which have naturally accumulated since the final Gates and Ehlers supplement (1948). An account of botanical history in the region, with full bibliography and an annotated list of those species reported in the literature but for which no accurately determined specimens have been found, is being published separately (Voss, 1956). It seems unnecessary to repeat here the background material, statements concerning important collectors, list of references, and similar material in this companion paper. The criteria for inclusion of species on the accepted list may well be again summarized, however. All species are accepted for which there are authentic specimens in herbaria so long as there are no indications on the label (or in published statements) that the collection represented a population growing under cultivation or directly persisting from cultivation. This means that (so far as the known evidence goes) an included species must at the time of collection have been reproducing itself or growing from seeds which were not planted. The present list differs from those of Gates and Ehlers by presenting new records only for the entire two-county region. Individual new records for each county would extend the report to unmanageable length. This list does supplement those of Gates and Ehlers, however, in that records are included for all species which they did not list–even the few which have been previously published elsewhere, as it has seemed useful to gather into one supplement the scattered records from the literature of the past half-century if these are verified by specimens. (The unverified reports, including those of Gates and Ehlers themselves, are accounted for in the companion paper previously cited, and reference to them is made here only if the correct determination for a misidentified collection is an addition to the list for the region.) Only species new to the region are included. Additional varieties and forms are not mentioned, since the space required would he considerable and since the importance of many infraspecific entities is not agreed upon by botanists. If a new record for a species can be clearly placed in a particular variety, however, this may be mentioned below. But it should be emphasized that failure to cite a variety does not necessarily mean that the nomenclaturally typical variety is implied; only if the specific epithet is repeated in varietal rank may this be assumed. In their final supplement, Gates and Ehlers (1948, p. 46) gave the total number of "species and varieties" in the region to be 1226. This figure (as in their previous statistical summaries of "species" evidently includes species, varieties, forms, hybrids whether nam d or designated by formula, and new names for species already reported under other names. As a consequence, the figure is quite meaningless. As my records now stand, the regional list includes 876 indigenous species and 307 non-indigenous ones. Since three species are represented by varieties in both categories, the total number of species is 1180 (based on a fairly conservative concept of species). Many are represented by more than one named variety or form, but these have not been tabulated. Approximately 40 of the species considered non-indigenous in our flora are native within a few hundred miles or less, but because of their occurrence as an occasional roadside or railroad waif or an apparent escape from cultivation it seems best to consider them adventive or introduced in the Douglas Lake region. In addition to the 1180 species in the region, more than 20 hybrids have been identified and, if new to the region, are reported below by formula or, whenever possible, by a binomial.