This largely midwestern taxon has been confused with saccharum and floridanum; further revision is needed. Initial studies of differences in DNA have not supported distinct taxonomic status for nigrum, but these analyses have not been linked with thorough analyses of morphological differences (Skepner & Krane 1997, 1998; Hilaire 1998). The leaves of nigrum appear generally distinctive: green and densely pubescent below (versus pale to glaucous, glabrous or pubescent); lobes shallower and fewer on average (in number of points) , more divergent and often with drooping tips; stipules often present on vigorous shoots (F, Cr, J, W), During the fall, leaves of nigrum become uniformly yellowish, while those of typical saccharum change from yellowish to reddish-brown or pinkish, remaining distinctly paler below. Also, the bark of nigrum can often be distinguished by its dark brown to blackish hues, generally in strips along furrows, which tend to become more pronounced in larger trees. The bark of typical saccharum has grayish-brown hues, or often slightly pinkish in older trees, and remains platy without dstinct furrows. In Ky. nigrum is usually concentrated on relatively moist or fertile sites, but further west it is often reported from relatively dry or fire-prone sites (Y). A. nigrum is often treated as a subspecies or variety of saccharum, since transitions are locally frequent, and sometimes named "var. schneckii" further west (Y). Intergradation is also suspected in some trees of the Bluegrass of Ky., but Gm noted that nigrum was distinct, locally predominant and typical of this region's old woodland pastures. In this region, Short (1828-9) did not separate nigrum from saccharum, noting: "The Sugar tree, as it is here universally called, is one of the most common of our forest trees, and perhaps in this particular locality, it attains its greatest altitude. As it does not materially interfere with the growth of grasses beneath it, it is often reserved in clearing ground, particularly in situations intended for pasture or meadows." Although much declined in farmed or urbanized landscapes, occasional large trees are remnants of the original mesic woodland. Potential champions are in FAYE ("saccharum" at 38.06230, -84.51917), 108 cm dbh, 33 m tall, 19 m wide; and in SHEL, 111 cm dbh, 22 m tall, 17 m wide (KDF 2020).