N. Vietnam, prov. Quang Ninh, distr. Hon Gai, Halong bay, Dan Go island. Secondary broadleaved evergreen forest on steep limestone slopes and vertical bluffs on elevations 0-100 m above s.l. Lithophyte forb on shady vertical cliffs of N exposition. Flowers blue with yellow center. Common.
NTH 2619 12 May 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)