Solidago gracillima Torr. & A. Gray is a very distinctive species in subsect. Maritimae. Only its lowermost stem leaves bases sheath the stem and these are oblanceolate and serrate and often absent by flowering. The stem leaves are quickly reduced and become entire and linear lanceolate to linear. The inflorescence usually has a few very long arching branches well below the terminal arching cluster of heads. Small plants can produce simple inflorescences like small versions of the the inflorescences of S. virgata (S. stricta sensu authors not Ait.). Semple (2012) clarified the limits of the species and noted that nomenclatural holotype exemplified the characteristic large plant inflorescence. The species is diploid 2n=18.
The species has been treated in various ways in floras resulting in confusion in the literature about the application of the name. Semple (2012) discussed the different applications of the name and how it had included several species in synonymy in some treatments or was itself included in other species. For example, Solidago austrina was included in S. stricta Aiton subsp. gracillima (Torr. & A. Gray) Semple in FNA (Semple & Cook 2006 FNA), but all are treated here as a separate species. In a multivariate analysis of the S. stricta complex, S. gracillima was well supported as a distinct species (Semple et al. 2016).
The species is native sandy soils at the the edges of woods and along road embankments in the southeastern U.S. It appears to be adapted to more seasonally dry habitats that typical for species in subsect. Maritimae. It can be locally common but populations are scattered. Its distribution is more restricted than indicated in the literature (e.g., FNA).