Heterotheca subaxillaris (Lam.) Britton & Rusby includes a complex of morphotypes that have been treated in multiple ways nomenclaturally. The complex of annuals and sometimes perennials in Mexico is very weedy (Semple 2006 FNA). Robust plants have broadly compound corymbiform arrays of heads on widely diverging branches. Leaves tend to be less densely spaced on the stems than in H. grandiflora and sessile upper stem leaves tend to be clasping and often more ovate.
Semple (2006) in Flora North America recognized just two geographically distinct races that differed in the numbers of large hairs on the ends of the phyllaries (Semple 2004) illustrated phyllary variation.
- ssp. latifolia (including H. psammophila and H. chrysopsides)
- ssp. subaxillaris
Semple, J.C. 2004. Miscellaneous nomenclatural changes in Astereae (Asteraceae). Sida 21: 759-765.
Last revised 20 April 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated
1-4. Heterotheca subaxillaris ssp. subaxillaris. 1. Habit, Semple & K. Shea 2031, Jones Beach, Long Island., New York. 2. Population of small plants, Semple 11604, Montgomery Co., North Carolina. 3. Small plant next to roadside barrier, Taylor Co., Florida. 4. Fruiting head, ray and disc florets.