FLORA OF VIETNAM Orchidaceae Dendrobium williamsonii Rchb.f.
Northern Vietnam, Ha Giang Prov., Quan Ba Distr., Can Ty Municipality, in the vicinity of Sin Suoi Ho village at right side of Mien River, about 1 km to the N from point 23°07′12′'N, 105°00′52′'E. Primary coniferous forest with Pseudotsuga brevifolia on remnant highly eroded limestone ridge at elev. 1000-1200 m a.s.l. Epiphyte on Pseudotsuga. Flowers: tepals yellowish-white, lip yellowish-white with red-orange center. Occasional. logging.