Stiff Leaved Showy Goldenrod

Solidago rigidiuscula (Torr. & A. Gray) Porter occurs on the eastern prairies and in prairie-like habitats from the eastern Great Plains to North and South Carolina.  Unlike other species in the S. speciosa complex, S. rigidiuscula drops it lower stem leaves by the time flowering begins.  Basal stem leaves similar to those of S. speciosa are present earlier in the growing season. Its mid and upper stem leaves tend to be crowded and stiff.  Fruits are usually sparsely strigose often only distally.  It was treated as S. speciosa var. rigidiuscula Torr. & A. Gray by Semple & Cook (2006 FNA).  In a multivariate morphometric study (Semple et al. 2017), the species separated well from S. jejunifolia, S. pallida, and S. speciosa,  The species is diploid 2n=18.  Semple and Cook (2022) published a cytogeography maps for S. rigidiuscula and related species.

It is a very rare plant in oak savannahs in southwestern Ontario, but becomes locally common in southern Michigan.  The range shown below is based mostly on literature and is tentative.  Collections from the Carolinas have been seen.  Collections from North Dakota and along the South Dakota-Nebraska border have not been seen.

Solidago rigidiuscula range Semple draft