FLORA OF VIETNAM Rubiaceae Ophiorrhiza sp. Northern Vietnam, Ha Giang Prov., Yen Minh Distr., Du Gia municipality, Giang Chu D village (Du Gia Nature Reserve). Primary broad-leaved evergreen closed wet forest on very steep slopes and cliffs of rocky ridges and mesae composed with solid marble-like stratified limestone. around point 22°55?53? N, 105° 08?32?E, 1718 m a.s.l. Herb 50 cm tall, common, on humus and wet soil in shade. Stem succulent, pale green, Petals white. CPC 282 15 May 2010. . Collectors: N. Q.Hieu, N.T. Hiep, N. T. Vinh, H.V.Chung (Funded by Critical Ecosystem Partnership Fund-CEPF through FFI)