Distribution map of Bulbophyllum concavibasalis
Bulbophyllum concavibasalis P.Royen, Alp. Fl. New Guinea 2 (1979) 167, fig. 64, P. van Royen, drawing, based on Brass 9531 (holo L (not found); iso AMES, BO)
Bulbophyllum loroglossum J.J.Verm., Orchid Monogr. 7 (1993) 163, fig. 117, J.J. Vermeulen, drawing, plant habit and flower analysis, based on Jongejan cult. (Schuiteman) 695 (holo L; iso AMES)
Bulbophyllum concavibasalis P.Royen, herbarium sheet, Brass 9531 (isotype specimen BO)