Looks like it - although Braem would probably have had a fit because of your grammar!
I's 'P. appletonianum fma. immaculatum'. 'Alba', 'immaculata, and likewise, is only used, when the genus of the genus, so to speak, is femininum, as for example is the case with Phalaenopsis, Cattleya or Sophronitis, that is now
seemingly included in the latter!