Camphor daisy

Heterotheca subaxillaris, the camphorweed or telegraph plant, is an erect, strongly aromatic annual to short-lived perennial herb of the Asteraceae native to the southern and central United States and northern Mexico, typically 30-150 cm tall. Stems are stout, much-branched in their upper portion, glandular-pubescent and emit a distinctly camphor-like odour when crushed. Leaves are alternate; lower leaves are petiolate, broadly ovate to oblong, 3-9 cm long and 1.5-4 cm wide, coarsely dentate or sinuate, with cordate to clasping bases on the upper cauline leaves which become smaller, sessile and entire. All leaves are densely glandular-hairy and rough to the touch. The inflorescence is an open, much-branched corymb of numerous small heads. Each capitulum is 1.5-2.5 cm across with 15-35 yellow ray florets surrounding a denser yellow disc of tubular florets, subtended by an involucre of several rows of narrow, glandular, acuminate phyllaries. Ray achenes are obovate, glabrous, lacking a well-developed pappus; disc achenes are pubescent and crowned with a double pappus of an outer ring of short scales and an inner ring of capillary bristles. The species colonises sandy disturbed soils, roadsides, dunes and old fields.