California Goldenrod

Solidago californica Nutt. is natived to southern Oregon and much of California except the Mohave Desert area in the southeastern portion of the state.  The species is distinguished from S. velutina by its more densely hairy stems and much more densely hairy peduncles and by its sparsely to moderately densely hairy upper peduncle bracts and narrowly ovate outer phyllaries.

Solidago californica range Semple draft

The species has been treated as S. velutina subsp. californica (Nutt.) Semple (Semple and Cook 2006) or placed in complete synonymy under S. velutina (Nesom 1989).  Two multivariate studies support recognition of the taxon at the species level.  Semple et al. (1990) compared S. californica to northern members of S. velutina (as S. sparsiflora), S. nemoralis subsp. decemflora and S. nemoralis subsp. nemoralis.  In a large multivariate study of the S. subsect. Nemorales (Semple et al. 2018), S. californica was found to be distinct from S. hintoniorum, S. mollis, S. nana, S. nemoralis, S. radula, and S. velutina (including S. sparsiflora). Solidago nemoralis, S. decemflora, and S. nana are now included in S. subg. Nemorales, and S. californica is included in S. [subg. Pleiactila sect. Unilaterales] subsect. Radulae (Semple and Beck 2021; Semple et al. 2023 in press).

Solidago californica is diploid throughout its range with a few tetraploids reported from Sonoma Co., California. Semple (2023) mapped the cytogeography of the S. californica.