Thanks Hien, for the photos, wait a couple days, I will take some, they are just starting to open over there...
The huonglanae variety in the trade is the vietnamese form of emersonii, some are more orange to very orange, some are all pink ( and very, very rare ! I think I saw only once a pic on interne, though I have seen maybe myself 3 or 4 plants in bloom,
www.paphs.net and emersonii I think ?), and some much, much larger, flatter and more "perfect" than the chinese emersonii.
I firmly believe that Emerson 'Doc' Charles emersonii was coming from Viet Nam. He said that his plant batch originally comes from Azadehdel with paph henryanums ( Azadehdel got his plants of henryanum from Viet Nam, there is nearly none in China, only very small populations that are the end of the range of henryanum) and I have seen that plant, still alive and multigrowth, in 1995 or 1996, it was really a "big baby", like the vietnamese emersonii.
I have seen once in bloom a hangianum x emersonii natural hybrid, not really beautiful for that specific plant.
About emersonii and its var huonglanae ( I think huonglanae should be kept 'alive' as a name for those vietnamese populations), as well as hangianum, they have very specific requirements in zinc, manganese, and some others. When they bloom, if they were borderline deficient to mildly deficient ( that is always the case with a normal feeding program !), the flower spike production drains some of those elements from the complete plant to the flower spike ( realize that they are not very fast growing, and suddenly, if you think about hangianum, the weight of the flower stem + the bloom is about the weight of 4-5 leaves !!!), resulting in a massive starvation of the plant.
Some elements are translocatable from older parts to the newer parts but NOT from the roots to the older parts, meaning you cannot "reload the engine". That's why many people kill some species after bloom ( and I paid enough foliar analysis and flower stem/flower mineral analysis to understand that mess !!!). A constant feeding program has to be implemented from the time the growth start. Even half way from blooming size is already too late to correct those timebomb deficiencies ( very well known in the horticultural world actually, but not documented yet specifically for orchids !).
The wild collected plants show clearly that hangianum usually make 1-3 'scale-like leaves, 2-3 real leaves, and bloom. I would say the complete growth is at the very most 2 years old from the time it started, most likely 1 year for some plants I have seen. The basic is simple : We do not know how to grow those plants correctly !!!