Subshrubs, succulent, minutely papillate to smooth, glabrous. Roots fibrous, sometimes thick and fleshy. Stems prostrate or climbing, green. Leaves cauline, opposite [alternate], petiolate, those of each pair equal; stipules absent; blade cordate [lanceolate], flat, margins entire. Inflorescences axillary [terminal], flowers solitary or in few-flowered clusters, sessile or peduncled; bracts absent. Flowers showy, campanulate, 1 cm diam.; hypanthium conic; calyx lobes 4, unequal, 2 larger and leaflike, 2 green, tapered; petals (including petaloid staminodia) 140, connate proximally, white, cream, yellow, or pink to purple; nectary absent; stamens 80, arising from hypanthium; pistil 4-carpellate; ovary inferior, 4-loculed; placentation axile; styles absent; stigmas 4, linear. Fruits capsules, hygroscopic, obconic; valves 4; valve lids and wings absent. Seeds 800, brownish black, flat, tuberculate; arils absent.