Mapping remains tentative. This southeastern tree of relatively deep swamps is most common in the lower Mississippi Valley. There are reliable records from s. Ill. (ML), s. Ind. (D) and w. Tenn. (including Reelfoot Lake close to Ky.; D. Estes, pers. comm.). However, the scattered possible colls. from river bottoms of w. Ky. are generally not complete enough for verification, lacking fruits (M, CW). A. drummondii is somewhat intermediate between rubrum/carolinianum and saccharinum in samara size (2.7-5 cm long with 2-4 cm wings), leaf size and shape (often more broad-based than carolinianum), but its mature leaves are more or less persistently whitish-tomentose below, versus usually less densely pubescent to glabrate in the other taxa (W). This taxon appears to be a pentaploid or hexaploid (2n = 65 or 78) that has arisen from hybridization (Y). The details of potential intergradation among all three taxa needs to be reassessed (Saeki et al. 2011); see also notes under A. carolinianum (?= A. rubrum var. trilobum).