Heterotheca mucronata Harms in Turner is native to northeastern Mexico. Two races are recognized based on differences in the stem and leaf hairiness and glandularity. Typical var. mucronata has long silky leaf hairs and is tetraploid (2n=36), while var. harmsiana hispid-strigose leaves and is diploid (2n=18).
Last revised 29 April 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated
Nesom (2020) treated var. harmsiana as H. harmsiana (Semple) Nesom separating it from the more rhizomatous H. mucronata by its woody taproot and caespitose growth form and by being less pubescent and more glandular.