N. Viet Nam. Ha Giang Province, Quang Ba District, Bat dai Son. Primary forest on limestone with Biota sp., Fraxinus, Quercus, Pseudotsuga, Acer and Taxus dominants along ridge and below peak at elev. 1100-1200 m (about 23°07′N 105°02′E). Occasional lithophyte open outcrops. Ovary green, tepals clear light orange. DKH 5112 5 April 2000