Deciduous trees with very shallow root system and stout, lenticellate twigs. Leaves opposite, exstipulate, simple, with dendroid trichomes. Flowers in axillary cymes, apparently paniculate at anthesis, borne on stout pedicels clad with fuscous, floccose, lanate indumentum of articulate and dendroid hairs. Calyx patelliform, obconical or subcampanulate, fleshy, unequally 5-lobed, the upper middle lobe slightly longer than the other 4. Corolla showy, zygomorphic, tubular or narrowly infundibular; tube constricted and slightly curved above base forming a tubular nectary; upper lip 2-lobed, reflexed at anthesis; lower lip 3-lobed, spreading. Stamens 4, didynamous, all fertile; filaments contorted near base; anthers divergent. Style equalling the longer stamens, glandular-papillose at least in lower part. Ovary bilocular with fleshy, hemispherical, rugose placenta. Fruit a loculicidal capsule with woody pericarp. Seeds very numerous, minute, winged, with endosperm.

A genus of 6 species, all native to China; two species have been introduced into cultivation in warmer regions. Represented in Pakisan by 1 cultivated species. 

Superficially very similar to Catalpa Scop. and at one time placed in the Bignoniaceae, but its technical floral characters refer it to Scrophulariaceae, in the family it is however rather anomalous and, along with Wightia Wallich, it is placed in its own tibe, the Paulownieae.