Dendrobium anosmum is native the Philippines, New Guinea, Thailand, and Sri Lanka. The genus Dendrobium contains approximately 900 species making it one of the largest genera in the Orchidaceae.
The center of diversity of the genus is in the Old World Tropics, with a large diversity of species in the Himalayas, Australia, New Guinea, and the Philippines.
(Staples, G. W. and D. R. Herbst. 2005. A Tropical Garden Flora: Plants cultivated in the Hawaiian Islands and other tropical places. Bishop Museum Press, Honolulu, Hawai’i.)