Shrubs with twining branches. Leaves alternate, entire. Inflorescence a pendent, few-flowered cyme, or flowers solitary, terminal or upper-axillary. Flowers subtended by small caducous bracts and bracteoles; sepals free; petals free, or partly united and forming a tube, spreading at least at the tips, much exceeding sepals; stamens free, anthers shorter than filaments, opening via 2 ventral slits; ovary stipitate, bilocular, chartaceous. Fruit a dehiscent capsule; seeds numerous.
Endemic Australian genus of 14 species, all but 1 species restricted to Western Australia.
Previously included in Billardiera. Marianthus is distinguished by its stalked ovary, long, usually curved style, and dehiscent fruits.