Climbers. Bark of twigs lenticellate, often warted. Inflorescences large, terminal thyrses leafy at the base. Ovules 2 per cell. In breaking the leaves no gutta-percha threads. Veins and nerves with well-developed tracheid sheath; Ca-oxalate crystals in the leaf parenchyma restricted to rows of cells of normal size adjacent to the tracheids of these sheaths.