Velvety or Three-nerved Goldenrod
Solidago velutina DC. is native to the western U.S. and the mountains in eastern Mexico. The species occurs in the Rocky Mts. and Great Basin from Montana and Idaho in the US to Zacatecas in Mexico in pine and oak woods and more open areas on sandy and rocky soils.
The species includes considerable variation in leaf shape and venation and inflorescence shape and branch density. Peduncles tend to be sparsely strigose and the phyllaries are usually lanceolate and lack hairs but may be slightly minutely glandular.
Nesom (1989) lumped S. californica, S. sparsiflora and S. velutina into a single species without infraspecific taxa. Semple et al. (1990) recognized S. californica and S. sparsiflora, but did not include S. velutina in the narrow sense in their multivariate study of S. nemoralis and some presumed to be related other species. In the FNA treatment of Solidago, the two races native to the U.S. were included in S. velutina as subspecies (Semple & Cook 2006 FNA).
The results of multivariate study of all taxa in subsect. Nemorales (Mack.) Nesom (Semple et al. 2018) indicated that S. californica should be treated as separate from a more eastern S. velutina, which cannot be split non-arbitrarily into northern and southern races. Thus, S. sparsiflora A. Gray and S. velutina ssp. sparsilfora (A. Gray) Semple should be treated as synonyms of S. velutina.
Based on an unpublished polygenomic study of the entire genus, Semple and Beck (2021) split subsect. Nemorales into two not closely related groups, S. subg. Nemorales (Mack.) Semple & J.B. Beck and S. [subg. Pleiactila sect. Unilaterales] subsect. Radulae (Rydb.) Semple & J.B. Beck that differed in rootstock, leaf venation, and stem and leaf hair stiffness traits. Solidago velutina has lower stem leaves that are somewhat trinervate, stiff hairs, and short to long rhizomatous rootstocks, which are typical traits of S. subsect. Radulae. The DNA results also indicated that S. velutina as treated here may need to be split into several species pending a more detailed molecular study with one or more species recognized in Mexico.
The species includes diploids 2n=18, tetraploids 2n=36, and hexaploids 2n=54. Semple (2023) mapped the cytogeography of the S. velutina.