The key difference between Z. lappaceum and Z. hypodiscus is in the ratio of the width to length of the flower. Z. lappaceum is wider than it is long and Z. hypodiscus is longer than it is wide. This plant as seen in the photos is longer than wide, favoring Z. hypodiscus. The opening (window) of Z. hypodiscus is up to half the length of the flower and Z. lappaceum is less than half. The window on this flower appears to be almost exactly half the length, which also favors Z. hypodiscus. This plant matches the Key found in "Icones Pleurothallidinarum" and the drawing of Z. hypodiscus in the Systemics of Zootrophion.