Ha Giang Prov., Bac Me Distr., Thuong Tan municipality. Primary broad-leaved humid evergreen forest on very steep slopes and along rocky ridge composed with solid crystalline highly eroded limestone at elevation 1200-1285 m a.s.l. around point 22°38’19.0’’N 105°17’06.5’’E. Lithophytic herb along shady stream canyon. Locally very common.