I was lucky enough to import a plant in the early 90’s from Wolfgang Bandisch who owned Sogeri Orchids in PNG. It was originally identified as Bulbophyllum adenambon, but this name was later put into synonymy with B. quadrangulare. The few photos that I have seen of B. quadrangulare shows a flower with lateral sepals in yellow to orange with basal red striping. It also has a dorsal sepal that approaches white, again with some red stripes. The plant that I received has flowers the most beautiful red to fuschia. My plant came from the Ymas Lakes and maybe this flower color prevails in that location. Or maybe I was lucky to get this special one. I will probably never know. This species is another one in the section Polymeres. Like others in this section, the flowers open wide in the morning until mid day and then are a bit bashful and close a little the rest of the time. In the case of B. quadrangulare, all the various forms the flowers take over the course of a day are equally attractive.