Border area between Phieng Luong municipality (Ha Giang Prov., Bac Me Distr.) and Sinh Long municipalitiy (Tuen Quang Prov., Na Hang Distr.). Primary broad-leaved humid evergreen and mixed forest on very steep slopes and along rocky ridge composed with solid crystalline highly eroded limestone at elevation 1100-1170 m a.s.l. around point 22°38’24.3’’N 105°20’21.3’’E. Terrestrial herb 1 tall on wet alluvial bottom of limestone mountain. Flowers yellow. Common.