Dendrobium flexicaule is accepted species in  the family Orchidaceae  subfamily: Epidendroideae, tribe: Dendrobieae, subtribe: Dendrobiinae,  
Genus Dendrobium   section: Dendrobium 
Infraspecific taxa recognized within Dendrobium flexicaule: infraspecific taxa
This species is found in China (SC. Sichuan to Henan).