Perennial herb to 1.5 m tall, rhizomatous. Stems hairy above, glabrous below. Basal leaves lanceolate, withering early. Stem leaves lanceolate, to 13 cm long, to 2 cm wide, margins sharply toothed, sparsely hairy. Capitula many in 1-sided racemes forming pyramidal panicles, to 4 mm across; late summer to autumn. Ray florets 10-17, to 4 mm long, yellow. Disk florets yellow.
North America
A number of varieties and subspecies are recognised, differing mainly in leaf, involucre and ligule characteristics.
S. odora Aiton from eastern USA is an erect aniseed-scented herb with entire leaves, capitula in 1-sided racemes forming panicles and 3-5 showy ray florets.
Source: (2002). Dahlia. In: . Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.