Alocasia ridleyi is similar to A. scabriuscula "LRO" in that it has thick or leathery leaves and maroon pinstriping on the petioles. A. ridleyi has similar inflorescences, but grows to a smaller mature size overall, and the leaves are much shorter as well, with a greater petiole length to leaf blade length ratio. Both A. ridleyi and A. scabriuscula "LRO" show affinities to such plants as A. chaii, A. reginae 'Miri', A. nebula 'Imperialis' and A. villeneuvii.
The inflorescences, opened and unopened, can be seen in the picture above. These are borne in clusters rather than a pair per leaf as in other Alocasia species.