FLORA OF VIETNAM Acanthaceae Phlogacanthus annamensis R.Ben.?
Quang Binh Prov., Minh Hoa Distr., Thuong Hoa municipality, around point 17°41′14.3”N 105°53′28.9”E.
Primary closed evergreen broad-leaved forest on very steep cliffy slope of remnant limestone mountain composed with solid highly eroded crystalline limestone at elevation about 700 m a.s.l.
Undershrub to 2 m tall on open wet mossy cliffy rocks. Flowers white. Not common.