Regarding the Vuylstekeara- our OCE/Big Bill has been spending some time with it and he said
"It is not Melissa Brianne. That is a much fuller flower.
The Wiz has twenty plus images posted of Beallara Marfitch. A couple have slender segments and darker color.
Marfitch is Charles M. Fitch x Oncidium Fermat. That could be it??"
