FLORA OF VIETNAM
Carlemanniaceae
Silvianthus tonkinensis (Gagnep.) Ridsdale

Ha Giang prov., Quan Ba distr., Tung Vai commune, Thung Pang village, around point 23°04ʹ28.9ʺN 104°55ʹ32.0ʺE, steep rocky slope to large deep cave composed with highly eroded marble-like white limestone at elevation 900–1000 m a.s.l. Secondary evergreen broad-leaved very humid forest with bamboo. Shrub 3-4 m tall on open wet rocky place. Not common. 17 October 2018, L. Averyanov, Nguyen Sinh Khang, T. Maisak, Truong Duc Thieu, VR 941 (HN, LE01049833).