Dendrobium obtusum is accepted species in  the family Orchidaceae  subfamily: Epidendroideae, tribe: Dendrobieae, subtribe: Dendrobiinae,  
Genus Dendrobium   section: Calyptrochilus 
Infraspecific taxa recognized within Dendrobium obtusum: infraspecific taxa
This species is found in New Guinea to Solomon Is. (Bougainville).