There is a large amount of confusion between D. polyanthum, D. primulinum and D. cretaceum. Kew in the POWO considers D. polyanthum and D. primulinum to be separate species, however, many sources lists them as synonymous and many of the photos (OW and orchidroots) has them lumped together as D. polyanthum. The IOSPE lists them as separate species. There is an exact match to this plant in the POWO as D. polyanthum. Kew considers D. cretaceum a synonym for D. polyanthum. H. P. Wood in "Dendrobiums" described D. polyanthum and states,: "Discussions about the legitimate name of all three (polyanthum, primulinum, and cretaceum) go back more than a century." Wood stated he studied the type specimens at Kew and agreed with Kew that the correct name is D. polyanthum.