Prairie Gray-stemmed Goldenrod
³§´Ç±ô¾±»å²¹²µ´ÇÌýdecemflora DC. is a tetraploid species native to the Great Plains (see map S. nemoralis). It is distinguished by the following set of traits: Pappus bristles usually exceeding ray floret corolla tubes and bases of disc corolla lobes; disc corolla lobes (0.6–)0.8–1.5 mm; involucres usually 4.6–5.8 mm; cypselae moderately strigose; basal leaves usually not crenate, often linear-oblanceolate. It was treated as a subspecies of S. nemoralis in Flora North America (), based in part on the assumption that it was closely related to and relatively recently derived from a diploid population of S. nemoralis (Semple et al. 1990). Recently it was determined that S. nemoralis,ÌýS. decemfloraÌý²¹²Ô»åÌýS. nana were members of one of the older lines of evolution in the genus S. subg. Nemorales (Mackenzie)ÌýSemple & J.B. Beck (2021) and it seemed more likely that S. decemflora had a now extinct diploid ancestor that was much older then previously assumed. There are multiple synonyms for this species; S. nemoralisÌý²õ³Ü²ú²õ±è.Ìýdecemflora (DC.) Brammall ex Semple, S. nemoralisÌý±¹²¹°ù.Ìýlongipetiolata (Mack & Bush) E.J. Palmer & Steyermark (refers to the sometimes linear oblanceolate basal leaves produced by the species). Names based on S. longipetiolata do not have nomenclatural priority.  Solidago decemflora is known throughout its range to be tetraploid (2n=36; trreated as a subsp. in Brammall & Semple 1990).
Brammall, R. A., and J.C. Semple. 1990. The cytotaxonomy of Solidago nemoralis (Compositae: Astereae). Can. J. Bot. 68: 2065-2069.
Semple, J.C., J.G. Chmielewski, and R. A. Brammall. 1990. A multivariate morphometric study of Solidago nemoralis (Compositae: Astereae) and comparison with S. californicaÌý²¹²Ô»åÌýS. sparsiflora. Can. J. Bot. 68: 2070-2082.
Semple, J.C. and J.B. Beck. 2021. A revised infrageneric classification of Solidago (Asteraceae: Astereae). Phytoneuron 2021-10. 1-6.
Last revised 16 April 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated
1-2. Solidago decemflora. 1. Small plant, Semple & B. Semple 11402, Crook Co., Wyoming. 2. Small plant, Semple & Brouillet 4469, Custer Co., South Dakota.