Heterotheca subaxillaris is an annual or biennial herb, taprooted, stem 0.2-1.5 cm tall (usually less than 50 cm); hairy, aromatic, sticky.
Leaves alternate, both basal and stem, stalk winged, upper leaves sessile, blade 2-9 cm long, 1-3 cm wide, reduced upwards, upper leaves broad, egg-shaped to oblong, base clasping stem, surface hairy-sticky on both sides, margins often toothed, the lower leaves deciduous as plant blooms.
Flowers yellow, rays 15-30, 1-2 cm long, disk fflowers yellow, heads 0.5-0.9 cm tall 0.7=1.2 cm wide across top, bracts sticky, to 0.8 cm long, overlapping, in several rows, tips hairy (use lens); infflorescence branched, with numerous fflower heads; blooms and fruits July-Sept. Pollinated by bees and some skipper butterflies (Hesperiidae), (Radford et al. 1968; Olsen 1997; Pyle 1981).
Fruit dry, 1-seeded achene, 3-angled, to 0.3 cm long, hairy, no plume.
Wetland status: UPL.
Frequency in NYC: Infrequent.
Origin: Native to Delaware and south.
Habitat: Dry, sandy soil of open areas, mostly in back dunes or sandy fill near shore. Often many together.