Vietnamese callosum, albino form. It has been previously known as 'Mr. Tran'. One cultivar exists so far ( and maybe actually that's the only "real" albino callosum anywhere left...). The flower is quite small, 4-5 cm maximum. The color is a very nice dark green, but the form is not that good, to say the least... All the Vietnamese callosum album are divisions of that plant, cultivated for a very long time in Da Lat.