Northern Downy goldenrod , verge d’or pubérulente
Solidago puberula Nutt. was devided into two subspecies in Semple & Cook (2006 FNA), but these are treated as separate species here based on addition study. Solidago puberula in the narrow sense is the more northern and high mountain taxon that has very short hairs on the stems and narrow long-attentuate phyllaries. Solidago pulverulenta has slightly smaller involucres on average and sometimes broader, acute phyllaries and usually more leaves per stem than S. puberula. Semple et al. (2017) included S. puberula and S. pulverulenta in a multivariate analysis of 14 species of S. subsect. Squarrosae. Semple et al. (2020) presented the results of a multivariate study of S. puberula, S. pulverulenta, S. roanensis, and S. sciaphila. The results indicated that S. puberula and S. pulverulenta differ on technical morphological traits, but ranges of variation in those traits overlap considerably. Semple et al. (2020) included a discussion of the nomenclatural history of treating S. pulverulenta as either a subspecies or a variety within S. puberula. The mostly allopatric ranges of distribution fit the Ehrendorfer (1968) definition of subspecies cited in Semple (1974), but currently in North America subspecies rank is more often considered to be a grouping category like subgenus or subfamily rather than a distinct infraspecific category as presented in Semple (1974) for the taxonomy of Xanthisma texanum DC. Semple et al. (2020) concluded that variety rank for S. pulverulenta within S. puberula was not adequate at indicating the ecological and morphology differences between the two taxa and species status was recommended.
The species is diploid with 2n=18.