This weird aroid from limestone of Southern Thailand and Northern Peninsula Malaysia has a unique bristly spadix protruding from its pitcher-like spathe. The original type was described by Masters in 1884, from plants mixed up with some Phillippines orchids. In 1896, another botanist Curtis collected more specimens off the Thai coast.
According to G. Gusman (2003), these represented 2 different subspecies, the more widespread subsp fimbriatum and the more restricted bakerianum. Amongst other characteristics, the former subsp has spathe that is stripped white while the latter is without stripe. Vegetatively, the former has 2 leaves while this one has one only. Geographically and in habitat, they are also quite different - the former is found extensively inland in North Malaysia and Thai border while the latter is found on isolated islands in W. Thailand only.
As noted by Gusman, I found this plant growing on limestone cliffs just a few metres above the sea and would no doubt be exposed to the sprays. That's an unusual habitat for an Arisaema.