Cao Bang Prov., Bao Lac Distr., Hong An municipality, Mi Lung village. Primary broad-leaved and mixed humid evergreen forest on very steep slopes and along rocky ridge composed with solid crystalline highly eroded limestone at elevation 1500-1550 m a.s.l. around point 22°50’01.3’’N 105°50’05.7’’E. Terrestrial herb in shady wet place among mossy boulders. Flowers white, tube with dirty violet apex. Very common.