according to internet citation, when this species was initially discovered, it was mistaken for catasetum callosum alba.
however, the labellum and the lateral sepals will enable one to tell the difference between a rectangulare and a callosum alba. the lateral margin of the lobe margin are parallel before they converge into each other at the lip apex. in callousm, the lib is triangular in shape;
the lateral sepals of rectagulare are with sickle shapre slightly while it is straight in the callosum.