That's a very good point. I've noticed the discrepancies among so called "Den. goldschmidtianum" and "Den. miyakei"...
According to the original article that declared the two as the same:
(taken from
Significant collections of Orchidaceae conserved in Herbarium Hamburgense (HBG) | SpringerLink)
"When describing D. miyakei, Schlechter
was unable to locate specimens of D. goldschmidtianum at Berlin for comparison. Examination of the holotype of D. goldschmidtianum, which includes a photograph
of a cultivated plant in flower, shows the
two concepts to be identical. Unfortunately,
this requires changing the name of D. miyakei, a minor horticultural species. Elizabeth Dauncey (K), who is currently monographing Dendrobium sect. Pedilonum,
agrees with this finding (pers. comm., 1994). "
Apparently it is more detailed in the article below, but I wasn't able to find a copy online. "Typification of Schlechter's East Asian Orchidaceae held at the Herbarium"
According to the Taiwan Biodiversity Information Facility (It's open access... so... I would take it with a grain of salt) that Den. goldschmitianum was originally identified in the Philippines while Den. Miyakei was identified in Taiwan. They mention that the Philippines population is taller and less purple.
So... the answer is... who knows... but seems like there are two separate populations of "Den goldschmidtianum" out there. Mine looks like Den miyakei... glad it's compact!