Big-toothed Canada Goldenrod
Solidago fallax (Fernald) Semple was treated as part of S. lepida or S. canadensis by various authors since it was first described as S. lepida var. fallax Fernald in 1915. Semple and Cook (2006 FNA) treated the species as S. lepida subsp. fallax (Fern.) Semple. Very recently, Semple (2013) proposed treating the taxon as a separate species and Semple et al. (2013) presented statistical support for recognizing the species and it two varieties.
Solidago fallax has broader mid and upper leaves than those of S. brendiae. Both species have inflorescences that are leafy compared to those of S. canadensis. The leaves usually have large coarse serrations along the mid and upper stem leaf margins. Involucre height is greater in S. fallax (diploid 2n=18, tetraploid 2n=36, and hexaploid 2n=54) than in S. canadensis (diploids only) with higher ploidy levels having larger involucres.
Semple (2013) recognized two varieties differing in the density of hairs on the stems and leaves: