Distribution map of Bulbophyllum nigrilabium
Bulbophyllum nigrilabium Schltr., floral analysis, drawing J.J. Smith, from Lam 1349
Bulbophyllum nigrilabium Schltr., floral analysis, R. Schlechter in Repert. Spec. Nov. Regni Veg. Beih. 21 (1928) t. 270, fig. 1032