Treatment remains tentative despite recent analysis of Engle-Wrye & Folk (2026). These are largely Appalachian plants that differ from var. brevipetala in having almost completely glabrous leaves, except for their ciliate margins and minutely glandular-puberulent petioles; there may also be subtle differences in texture and color. In contrast, var. brevipetala generally has hairs on both leaf surfaces (strigose above), although either surface can be thinly hairy or glabrate in some cases. At GH and elsewhere, there are colls. of similar plants from DC. Ga., N.C., S.C., Tenn. and Va. The name "Heuchera glauca Raf." is written on a few of the older colls., and should be researched further with other potential types (Wells 1984). Engle-Wrye & Folk (2026) stated: "Heuchera americana var. americana contains a unique ancestral population (green in Figs. 2, 9), and a morass of intergrades involving the geographically adjacent taxa H. caroliniana (cerulean blue, Figs. 2, 9) and H. fumosimontana (light blue, Figs. 2, 9). The former account for H. americana accessions from North Carolina that placed with H. caroliniana in the ASTRAL phylogeny (Fig. 1). Strangely, these specimens do not at all morphologically intergrade with either H. caroliniana (see also Wells 1984, as this was her main reasoning for species rank) or H. fumosimontana (see Taxonomic Treatment below). Heuchera americana var. americana is, in summary, morphologically similar to other adjacent taxa, shows the most profuse introgression, and is the least easily diagnosable of the Heuchera americana varieties except by exclusion." B noted apparent hybrids with H. longiflora from LETC (check US). H. hispida Pursh (= H. americana var. hispida (Pursh) Wells) also has generally glabrous leaves, but its larger flowers with purple petals are distinct; see notes under that name (and pubescens).