Herbs perennial. Rootstock thick. Stems arising from rootstock or persistent basal part of flowering stems, simple, glabrous, rarely pubescent. Leaves alternate or opposite, petiolate or sessile; leaf blade flat, margin serrate or crenate. Inflorescences terminal, cymose with 3 main branches, bractless, many flowered. Flowers sessile or nearly so, bisexual, mostly 5-merous. Sepals basally connate, fleshy, spurless. Petals spreading at anthesis, nearly free, bright yellow. Stamens 2 × as many as petals, in 2 series. Nectar scales entire or apex emarginate. Ovaries and follicles with adaxial outgrowth. Styles short, oblique or spreading at flowering. Follicles many seeded. Seeds striate.