FLORA OF VIETNAM Orchidaceae Callostylis rigida Blume
Son La Prov., Son La City, Chieng Co Municipality, around point 21°18′24”N 103°52′53”E.
Secondary evergreen dry open broad-leaved forest on very steep rocky slopes and on tops of remnant mountain composed with highly eroded marble-like solid crystalline limestone at elevation 800-900 m a.s.l.
Lithophytic creeping herb on open rocky outcrops. Flowers dull yellow-orange, lip dull violet. Very common.