Solidago spellenbergii Semple was recently described (Semple 2017) from a single collection from Parque Nacional de Cascada Basaseachic, Chihuahua, Mexico: R. Spellenberg & D. Jewell 9266 (holotype: NMC; isotype: MEXU, digital image). The species differs from S. wrightii in having long, narrow stem leaves, heads with nearly smooth phyllaries, and fruits with very few hairs. Both species were included in a multivariate analysis of all taxa in Solidago subsect. Thyrsiflorae (Semple et al. 2017). More collections of S. spellenbergii are needed to determine its range of morphological variation and details of preferred habitat. The chromosome number is unknown.