From the Latin urceolus — a little pitcher, alluding to the shape of the flowers.
Twiners or lianas, evergreen; latex white. Stems woody, without spines. Leaves opposite, stalked; blade well developed, mucilage glands absent at base. Inflorescence terminal or axillary, paniculiform. Flowers scented, stalked. Corolla bell- to urn-shaped; tube bell-shaped; lobes convolute in bud, overlapping to the right. Corolline corona absent. Stamens enclosed, attached near base of corolla tube, converging and sticking to style head. Disk annular or of 5 lobes. Fruit of separate carpels, of 2 woody follicles, tapering to each end, terete, dehiscent ventrally. Seeds numerous, narrow-elliptic, flattened, not winged, comose at micropylar end.
One species is cultivated.
Twiners, leaves opposite, flowers less than 5 mm long.
About 25 species in Asia and Malesia.
Source: (2002). Apocynaceae. 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.