Paphiopedilum primulinum var. flavum ‘Grace’ - These produce striking yellow flowers that can bloom sequentially for two years on a single spike!

 Paphiopedilum primulinum var. flavum ‘Grace’
     Native to northern Sumatra. We have a couple of these that bloomed sequentially for nearly two years on single spikes!! Often only one flower is open at a time, but the nearly constant show is much appreciated.

Note: this flower photo is of another of our primulinums.