After M. Gaillard de Charentonneau, an 18th century French magistrate and patron of botany.
Annual to perennial herbs or rarely subshrubs, usually hairy. Stems erect or ascending. Leaves basal and/or along stems, alternate, margins entire, toothed or divided, sessile or petiolate. Capitula radiate or rarely diskoid, terminal, solitary or a few in corymbs, usually on long stalks. Involucral bracts in 2 or 3 rows, overlapping, unequal, reflexed in fruit. Receptacle with scales, convex. Ray florets sterile or female, usually ligulate, yellow to crimson with yellow to purple tips. Disk florets bisexual, tubular, yellow or purplish. Achenes obpyramidal, woolly. Pappus of membranous scales, the midrib extended into a point.
Two species have become weakly naturalised in Australia.
Reflexed involucral bracts in fruit; obpyramidal woolly achenes with prominent scales.
About 28 species from N and S America.
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.