Fls perfect, irregular, showy, 5-merous, in compound cymes; calyx sts bilabiate; corolla campanulate to funnelform, sts bilabiate. Stamens epipetalous, us. 4, didynamous, with a posterior staminode; anthers opening lengthwise. Disk hypog.; ovary superior, 2-carpelled; placentae parietal or on septum, ovules ∞. Style simple, stigma 2-lobed. Fr. us. a 2-valved capsule. Seeds often winged, without endosperm. Lianes, shrubs or trees with opp., decussate, simple or pinnately compound, exstipulate lvs. A mainly tropical family of c. 110 genera and 750 spp.

Trees, shrubs, often climbing, occasionally herbaceous. Branches often glandular near nodes, twining in some lianes. Lvs usually opposite, rarely alternate, exstipulate (outer bud scales may simulate stipules), sometimes simple, more commonly pinnate or digitate, often the terminal leaflet forming a tendril. Infl. terminal or axillary, racemose or paniculate, sometimes cauliflorous, occasionally fls solitary; bracts and bracteoles caducous. Fls ☿, zygomorphic to varying degrees, often large and showy. Calyx campanulate, 3-5-lobed or toothed, sometimes truncate. Corolla with 5 imbricate lobes, slightly to strongly 2-lipped; tube cylindric to campanulate. Stamens often 4 and didynamous, less commonly 2, the fifth stamen represented by a short staminode or 0, sometimes 3 staminodes present and only 2 stamens fertile; anthers connivent in pairs, rarely free, 2-locular. Hypogynous disc usually present around ovary. Ovary superior, generally 2-locular and 2-carpellate, sometimes 1-locular with 2 parietal placentae. Ovules numerous. Style 2-lobed. Fr. usually a 2-valved capsule, less commonly indehiscent and fleshy. Seeds often compressed and winged, non-endospermic; embryo straight.