Monsanto, 3rd, C, 258
Proceedings of the Royal Horticultural Society of London 3: 189–190. 1863. (Proc. Roy. Hort. Soc. London
Type cited as "Bignonia unguis" on p. 189, with the combination made on p. 190 as "Doxantha unguis: Bignonia idem. Linn., ....Plum. Amer. tab. 94". Thus this seems a clear reference to the basionym with an error, which does not invalidate the name (Art. 33.2).