Mapping is tentative due to frequent misidentifications and uncertain wild versus cultivated status. The main range of this widely planted southeastern tree is considered to have been mostly on the Gulf Coastal Plain from Ga. to La. (Little 1971; W; R. Olsen, pers. comm.). Its status in Ky. and Tenn. remains somewhat uncertain. All Ky. records may come from escaped plants, but native status has been suggested in MCLE, MCRE, TRIG, WHIT and perhaps elsewhere (Clark & Bauer 2001; CW, M). C. bignonioides is often confused with speciosa, especially without its distinctive smaller flowers and fruits (Gm, F, Cr, J, Y; R. Olsen, pers. comm.). Leaves of bignonioides tend to be smaller (mostly 8-22 cm long versus 15-30 cm including petiole), less long-tapered at apex (ca. 1 cm versus 2 cm), more persistently pubescent (with more appressed stellate hairs versus curly unbranched ones), and more fetid-smelling (perhaps associated with iridoid glucosides such as catapol and catalposide), Both species are reported to develop foliar nectaries in axils of major secondary veins (which attract ants), especially when damaged by the catalpa sphinx moth (Ceratomia catalpae), but in bignonioides these nectaries may be larger (ca. 2 mm wide versus 1 mm) and more consistently present (Ness 2003). Its bark is initially light brown (versus reddish-brown); older trunks have distinctive short thin scaly plates (versus elongated ridges and furrows); mature trees tend to be shorter, with more spreading branches. However, identification is often difficult, and there is genetic evidence that some cultivated plants are derived from hybridization (R. Olsen, pers. comm.).