Not particularly helpful to Aaron, but at the recent Paph Guild meeting, Frank Cervera expressed doubt that exstaminodium is a species distinct from humboltii. He explained that exstaminodium is a humboltii in every way, except for the lack of a staminode. He pointed out that it can only be found within the known range of humboltii. He noted that, when it was first described, it was the only Phrag species known to occur in a natural population that did not have a staminode. However, on a trip to Ecuador and Peru, Frank came across a large population of boisserianum with no staminode. In addition, at the 2017 WOC in Ecuador, he was shown a photo of a group of flowers growing along the Columbia border that included several flowers of schlimii without a staminode. Thus, he questions the species status based on a lack of a staminode.
I’m no taxonomist, but I thought this was kind of interesting.