Heterotheca subaxillaris (Lam.) Britton & Rusby is spreading as a introduced weed along dry sandy roadsides, trails, and along railways in immediately adjacent Indiana, and will doubtless be found in Michigan eventually. Though the relatively large yellow-rayed heads are similar to our other two species in form, the leaves are broader and clasp the stem, unlike the narrow, sessile leaves of our two species. 

1. Plants tall (over 0.5 m), erect; leaves mostly acute, with stalked glands (at least beneath).

H. camporum

1. Plants low (up to ca. 0.5 m), ± spreading and several-stemmed or -branched; leaves mostly obtuse (but mucronate), eglandular.

H. villosa