Western Rough Goldenrod
Solidago radula Nutt. is native to the open rocky places, dry woods, especially calcareous soils in the western part southeastern U.S. with infrequent, scattered populations further east
It is distinguished by its finely scabrous leaves that are either not 3-nerved or only weakly so (Semple & Cook 2006 FNA). It is highly variable in inflorescence shape and can be similar to S. nemoralis or S. velutina in general appearance. Leaf shape is similar to some plants of S. mollis to which it is likely closely related. Shoots develop from either a short-branched caudex or elongated rhizomes. It can be similar to S. hintoniorum, native to northeastern Mexico.
In a multivariate study of S. subsect. Nemorales (Semple et al. 2018), specimens of S. radula were placed in the classificatory analysis into either S. radula or S. mollis with 1 specimen placed into S. californica. Tetraploids of S. radula were placed into S. mollis, which is polyploid.
The species includes diploids 2n=18 and tetraploids 2n=36.