N. Vietnam, Prov. Bac Can, limestone mountain pass Gio on car road from Hanoi to Cao Bang sity near Ngon Son town at 800-900 m alt. Secondary shrubs and grass communitys on high limestone massif. Epilitic herb on open vertical limestone mesas bluffs at 700-800 m alt. near road. Flowers pale blue. Common. VH 4990 28.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)