Dendrobium petrophilum (Kraenzl.) Garay ex N.Hallé, a well-named species describing its unusual chasmophytic ecology

Dendrobium petrophilum (Kraenzl.) Garay ex N.Hallé was a species only known from the type specimen and considered doubtful. Since it has been recently relocated in its locality surrounding areas, we were able to compare endemic closely related well species, oppositifolium N.Hallé. We confirm D. as distinct based on morphology very special ecology. Both are fully described, compared, illustrated. Comparative tables given English French. also discuss their ecology, distribution, phenology IUCN assessments made by local Endemia Red List Authority.