After Johann Gottfried Zinn (1727–59), Professor of Botany at Göttingen.
Annual or perennial herbs or subshrubs, hairy. Stems erect or ascending, much-branched. Leaves along stems, opposite, entire, sessile or shortly petiolate. Capitula radiate or diskoid, terminal, solitary, with hollow, often inflated stalks. Involucral bracts in 3 or more rows, overlapping, unequal. Receptacle with scales, concave to conical. Ray florets female, often ligulate, white, yellow, orange, pink, red or purple. Disk florets bisexual or functionally male, tubular, yellow or orange. Achenes obovoid, 3-angled or compressed, sometimes corky, smooth or warty. Pappus of 1 or 2 short bristles, or absent.
One species has become weakly naturalised in Australia.
Capitula often on long, inflated, hollow stalks; receptacle scaly.
About 22 species from N, C and S America.
Robinson & Greenman (1896).
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.