Greek tragos — billy-goat, pogon — beard, an allusion to the pappus.
Perennial, annual or biennial herbs, taprooted, glabrous to hairy. Stems erect, simple or little-branched. Leaves basal and along stems, alternate, entire, sessile. Capitula 'radiate', terminal, mostly solitary, with stalks. Involucral bracts in 1 row, somewhat joined at base, overlapping, equal, elongating in fruit. Receptacle pitted, convex. Florets bisexual, ligulate, yellow, purple or violet. Achenes cylindrical, ribbed, long-beaked. Pappus of barbed or feathery bristles.
Two species have become sparingly naturalised in Australia.
Narrow grass-like leaves; all florets ligulate; achenes large and beaked.
About 110 species from Europe, Asia and North Africa.
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.