Downy Ragged Goldenrod
Solidago petiolaris Ait. is native to the southern U.S. from northeastern New Mexico to North Carolina and south to Texas and Florida with disjunct populations across central Texas into northern Coahuila, Mexico. The species is variable in leaf surface traits and generally has only small teeth or none on the leaf margins (Semple & Cook 2006 FNA). Middle and upper stem leaves have a short well defined petiole, as due leaves of S. wrightii. The inflorescence is often elongated. Lower stem leaves are typically absent at the time of flowering. Nesom (1990) recognized and mapped the distribution of the varieties, which were not recognized in the FNA treatment. The species is diploid 2n=18 throughout its range with one tetraploid 2n=36 reported from North Carolina; reports from other locations were based on incorrectly identified vouchers.
Three varieties are recognized here based on the multivariate study S. subsect. Thyrsiflorae by Semple et al. (2017). Nesom (2008) reviewed problems with delimiting the proposed varieties in S. petiolaris and mapped the distribution of three varieties. Semple et al. (2017) reported on several multivariate analyses and concluded that phyllary traits were best in defining the varieties along with leaf traits:
- var. petiolaris; middle and inner series phyllaries sparsely to moderately strigose, sometimes minutely glandular; mid and upper stem leaves lanceolate-elliptic to ovate-elliptic, involucres at anthesis 6-8 mm (mean = 7.5 mm), mid leaves 12-21(-32) mm wide; North Carolina to N Florida west to Alabama, disjunct in east Texas
- var. angusta; middle and inner series phyllaries glabrous, usually minutely glandular or resinous and shiny; mid and upper stem leaves usually narrowly lanceolate, rarely broadly lanceolate to ovate, green to shiny silvery; Missouri to Louisiana west to SE Kansas to eastern and central Texas, disjunct in N Coahuila
- var. wardii; middle and inner series phyllaries sparsely to moderately strigose, involucres at anthesis 4.3-6.3(-7; mean = 5.3 mm); southern Nebraska, Kansas, western Oklahoma, western Texas, NE New Mexico, SE Colorado
Nesom, G.L. 2008. Taxonomic review of Solidago petiolaris and S. wrightii (Asteraceae: Astereae). Phytologia 90: 21–35.
Semple, J.C., Y. Ma, U. Naik, N. Steenhof, and L. Tong. 2017. A multivariate morphometric analysis of Solidago subsect. Thyrsiflorae (Asteraceae: Astereae). Phytoneuron 2017-67: 1–35.
Last update 26 October 2017 by J.C. Semple
© 2017 J.C. Semple, including all photographs unless otherwise indicated