Quang Binh Prov., Tuyen Hoa Distr., Lam Hoa municipality, near Ca Tang bridge crossing Gianh River, around point 17°57’31”N 105°48’43”E. Secondary broadleaved evergreen forest along river valley composed with stratified soft shale limestone at elev. about 60 m a.s.l. Shrub 2-3 m tall along rocky river valley. Flowers greenish to dull reddish. Main dominants of riparian shrubs along rocky river valley.