This largely midwestern tetraploid (2n = 52) has been confused with the more southeastern diploids, hugeri and biltmoreana (FNA 26). See notes under those two taxa, which have distinctly narrower leaves that tend to be less numerous (on average). In the upper midwest there appear to be stabilized hybrids of ecirrata with lasioneura known as S. illinoensis Mangaly, and these may be expected in Ky. (FNA 26). S. illinoensis differs from ecirrata in its more numerous flowers (usually more than 25), on longer peduncles; its taller stems, with more leaves and frequent tendrils (versus virtually never); and its narrower leaves. Withour flowers or fruits, even typical ecirrata is difficult to distinguish from stunted plants of lasioneura (especially in shade), but it may be more pubescent generally over lower leaf surfaces (versus concentrated along veins).