Solidago discoidea (Brintonia)

Solidago discoidea (Ell.) Torr. & A. Gray has been treated as the only species in the genus Brintonia E.L. Greene as B. discoidea (Ell.) E.L. Greene.  Brintonia and Chrysoma were reported to form a clade that was the sister to Solidago (Schilling et al. 2008) based on ITS and ETS gene sequences. The polygenomic DNA research by Semple et al. (2023) found the species to be nested within S. subg. Solidago and Semple and Beck (2021) placed it in S. sect. Brintonia (Greene) Semple & Beck between S. sect. Squarrosae Semple & Beckand S. sect. Thysiflorae. Rayless Mock Goldenrods are herbaceous perennials found on sandy soils, rich, sometimes swampy woods on the coastal plain in Alabama, Northern Florida, Southwestern Georgia, Louisiana and Mississippi. Heads lack ray florets and have whitish disc florets tinted with purplish red. The pappus bristles are also usually distinctively purplish red. Flowering from August to October.

The species is diploid (2n=18). Semple and Cook (2022) published cytogeography maps for S. discoidea and related species.

Semple, J.C. 2006. Brintonia E.L. Greene. pp. 106. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part. 2. Astereae and Senecioneae. Oxford University Press.

Schilling, E.E., J.B. Beck, P.J. Calie, and R.L. Small. 2008. Molecular analysis of Solidaster cv. Lemore, a hybrid goldenrod (Asteraceae). Journal of the Botanical Research Institute of Texas 2: 7-18.

Semple, J.C. and J.B. Beck. 2021. A revised infrageneric classification of Solidago (Asteraceae: Astereae). Phytoneuron 2021-10. 1-6. 

Semple, J.C., McMinn-Sauder, H., Stover, M., Lemmon, A., Lemmon E., and J. B. Beck. 2023. Goldenrod herbariomics: Hybrid-sequence capture reveals the phylogeny of diploid Solidago. Amer. J. Bot. 110(7): e16164.https://doi.org/10.1002/ajb2.16164

Last revised 6 April 2025 by J.C. Semple

© 2025 J.C. Semple, including all photographs unless otherwise indicated