Greek hymen — membrane, stemon — stamen, a probable allusion to the apical anther appendage.
Annual herbs. Stems erect. Leaves basal and along stems, alternate, margins toothed to lobed. Capitula radiate, terminal, solitary, on long stalks. Involucral bracts in 2 or 3 rows, overlapping, unequal. Receptacle convex to conical. Ray florets female, sterile, ligulate, white. Disk florets bisexual, tubular, yellow. Achenes 5-6-ribbed. Pappus a flimsy membranous crown.
Corolla tube of disk florets basally swollen in fruit.
2 species from the Mediterranean region.
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.