Stiff-leaved Goldenrod
Solidago rigida L. is the most widely distributed species in subsect. Ptarmicoidei. It occurs on prairies, oak savannahs and open woods from Alberta to southern New England and south to New Mexico and eastern Georgia. The yellow rayed species is distinguished by its flat-topped inflorescence, multi-veined phyllaries, and flat, ovate upper stem leaves (Semple & Cook 2006 FNA). Three subspecies are recognized based on differences in leaf and phyllary pubescence (Head & Semple 1988). I have recently considered separating off the more glabrous subsp. glabrata as a separate species but decided not to do so after reviewing the reasons for not doing so presented in Heard & Semple (1988). The species includes diploids (2n=18) and tetraploids (2n=18).
1. Outer series phyllaries pubescent, leaves and stems hispid to densely so
2. Inner series phyllaries conspiculously pubescent, often linear, pubescence of leaves and stems fine and very dense (>50 haris/mm2) subsp. humilis
2. Inner series phyllaries glabrate to very sparsely pubescent, oblong and bluntly rounded; pubescence coarsely hispid (<50 hairs/mm2) subsp. rigida
1. Outer series phyllaries glabrous, leaves and stems glabrous to somewhat hispida ssp. glab subsp. glabrata
Heard, S.B., and J.C. Semple. 1988. The Solidago rigida complex (Compositae: Astereae): a multivariate morphometric analysis and chromosome numbers. Can. J. Bot. 66: 1800-1807.
Last revised 16 November 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated.