Paph. hookerae vs Paph. volonteanum
Some taxonomists recognize both plants as distinct species, while other botanists classify one species only as a variety of the other species.
paper hookerae is found in southern Borneo in Sarawak and West Kalimantan at an altitude of 600-800 meters.
paper volonteanum is only found in Sabah (North Borneo). Some plants are found at an altitude of 600-800 meters but can also be found at altitudes of 2000 meters on Mt. Kinabalu and near the town of Sepilok/Sandakan. The undersides of these plants are always purple.
Since both types are similar at first glance, I will show both types next to each other here. This makes it easier to spot the differences:
While the staminode at the Paph. hookerae at an angle of almost 45° is the angle at Paph. volonteanum significantly smaller.
Here is a side-by-side comparison of both types:
Two other plants in comparison. the paph hookerae the shoe was removed during pollination:
With another Paph. volonteanum the staminodium is bent even further:
More pictures of the two species can be found here: