After James B. Bolton (1758–99), an English botanist.
Perennial herbs, virtually glabrous. Stems erect or ascending. Leaves basal and/or along stems, alternate, entire or toothed, sessile. Capitula radiate, in terminal corymbs, with short stalks. Involucral bracts in several rows, overlapping, unequal. Receptacle hemispherical or conical. Ray florets female, white, pink, blue or violet. Disk florets bisexual, yellow. Achenes obovate, compressed, winged, glabrous or sparsely hairy. Pappus a minute crown or scales, usually with 2 longer, barbed bristles.
Winged achenes; pappus a crown or scales and usually with 2 barbed bristles.
5 species from Central & eastern North America.
Source: (2002). Asteraceae. 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.