More or less twining shrubs. Leaves alternate, entire or sometimes shallowly lobed or toothed. Inflorescence a terminal cyme, or flowers solitary and terminal or axillary. Flowers subtended by 1–several caducous bracts; bracteoles present or absent; sepals free or shortly united near base; petals free, or partly to largely united and forming a tube, spreading at least at the tips, much exceeding sepals; stamens free, anthers sometimes connate at their tips, forming a cone around the style, opening via 2 ventral slits; ovary 1–2-locular. Fruit a more or less succulent, cylindric to ovoid berry; seeds numerous.
Endemic Australian genus of 23 species.
Now includes Sollya Lindl. and Pronaya Hugel ex Endl.
Cayzer, L.W.; Crisp, M.D. & Telford, I.R.H. (2004). Cladistic analysis and revision of Billardiera (Pittosporaceae), Australian Systematic Botany 17(1): 83-125.