I acquired Hoya pubicalyx “Black Dragon” around 14 months ago along with its counterpart “White Dragon.”  Joni at SRQ Hoyas imported it from Forrest Treasures in the Philippines. It is a very unusual pubicalyx in that the leaves are all lime green with no markings at all.  My plant has just bloomed under the relatively low light conditions of my grow tent so it is not nearly as black as the photo on the Forrest Treasures Website.  I was very interested in the origins of this plant asked George Mendoza the owner of Forrest Treasures about it.  Here is his reply:

The H. pubicalyx “Black Dragon” is not a hybrid. It was collected along the shorelines hanging on a cliff in western part of Luzon Island here in the Philippines. It has it’s counter part the “White Dragon” soon to be name H. celata. I’m glad to know that you like the “Black Dragon”.

This is truly a fantastic plant that blooms well and very dark even under grow lights.  I can enthusiastically recommend it to everyone. Wonderful plant!!!!!!

Hoya pubicalyx ‘Black Dragon’ is Really Almost Black!