Solidago brendae Semple (2013) is the most recently described species in S. subsect. Triplinerviae. Fernald (1915) treated the taxon as S. lepida var. elongata (Nutt.) Fern., which was a misapplication of the name S. elongata Nutt. to this species native to eastern Canada. It is common in the Gaspé Peninsula and along the north shore of the St. Lawrence R., in northestern Québec. It occurs in western Newfoundland and in scattered locations in New Brunswick, Prince Edward Island, and Cape Breton, and Nova Scotia in eastern Canada. It is known from several locations in Maine and possibly occurs in northern Maine as well. The range extends across northern Quebec toward James Bay in scattered locations and is native or introduced in scattered locations in northern Ontario as far west as Red Lake. Semple and Gilman (2015) reported the presence of S. brendae in northern Vermont. The species was not included in Semple and Cook (2006, Flora of North America). Semple (2020) discussed why the name S. brendae has been taken up here rather than the original form of the name S. brendiae as published.
Solidago brendae is distinguished from S. canadensis by the branching pattern of its inflorescences and by having usually much longer upper leaves that extend into the inflorescence and heads with more ray florets. Leaves can have large sharp serrations or be entire. Solidago brendae appears to replace S. canadensis north of roughly 46° N latitude.
Solidago brendae is similar to S. fallax but has narrower middle and upper stem leaves. Semple et al. (2013) presented a multivariate morphometric analysis that helped determine which technical characters distinguished these three eastern species from each other and from the more western S. lepida and S. elongata.
Solidago brendae is a diploid species occurring on calcareous sand and gravel soils, sandy clay loam soils along stream margins and banks, road sides and wet ditches, recently cleared land, disturbed ground, gravelly shores.
The species is named in honor of Brenda Semple the author's wife and companion on field trips for more than four decades and was co-collector of the type specimens Semple & Semple 11437 (WAT, MO, MT, UNB).
Semple (2016) documented a Solidago bicolor × S. brendiae hybrid using multivariate morphometric analysis of specimens of S. bicolor, S. brendae and S. canadensis. The hybrid was first reported by Hinds (1984) as S. bicolor × S. canadensis; the subsect. Triplinerviae parent was actually S. brendae. Semple (2020) documented a Solidago brendae × S. sempervirens hybrids using multivariate morphometric analysis of specimens of S. brendiae, S. canadensis and S. sempervirens.