Looked it up in Orchidwiz. It does list a Den. densiflorum, with a solid yellow flower. Here's the reference:
"Dendrobium densiflorum" Lindl. in N.Wallich, N.Wallich, Pl. Asiat. Rar. 1: 34 (1830)
Yours sure looks like Den. thyrsiflorum to me. I'm no expert on the genus - there may be others that look similar. But it sure looks like it... it definitely looks nothing like what Orchidwiz shows...
IOSPE photo looks the same - lots of butter-yellow flowers. No mention of a "luteo-alba" variety. (I did an Orchidwiz search on Dndrobium (containing "luteo") to see if anything came up. Nope, nothing close)
Then I changed approach... looked up Den. thyrsiflorum in Orchidwiz, and looked at the "Names" screen to find possible names that might have been used at some time. Bingo.
1869 Dendrobium densiflorum var. alboluteum Hook.f.
Assigned to its own species, Den. thrysiflorum in 1871
So it's a synonym or obsolete name for Den. thyrsiflorum (and misspelled on the tag that it came with)