6. B. salmoneum Averyanov & Vermeulen (2012: 128, fig. 1f & 3).

Type:— VIETNAM, Quang Binh Province, Minh Hoa District, Thuong Hoa Municipality, environs of Mo O O O Village, around point 17°39′31.7″N 105°54′48.2″E, primary broad-leaved closed forest on very steep rocky slope of remnant mountain composed of highly eroded solid crystalline limestone at elevation of 400–500 m a.s.l., creeping epiphytic on tall tree, not rare, 23 July 2011, N. T. Hiep, L. Averyanov, N. S. Khang, N. Q. Vinh, CPC 3657 (LE01057821 http://en.herbariumle.ru/?t=occ&id=8321, LE 01087269 http://en.herbariumle.ru/?t=occ&id=18990 photos, LE 01087271 http://en.herbariumle.ru/?t=occ&id=18992 drawing) .

Habitat and phenology: —Evergreen broad-leaved primary limestone forests at elevation of around 400–1000 m a.s.l. Trunk and branch epiphyte. Flowering in June – July.

Distribution: — VIETNAM (Quang Nam, Quang Binh, Gia Lai, Kon Tum, and Dak Lak provinces). Thailand.

Studied specimens:— THAILAND, wild collected plant originated from Thailand, cultivated in private garden of B. Q . Viet in southern Vietnam, AL s.n., 19 October 2017, L . Averyanov (LE01087720 http://en.herbariumle.ru/?t=occ&id=42947 photos) . VIETNAM, plant cultivated in Lam Dong province, Di Linh District, originated from Quang Nam Province, 16 June 2020, Truong Ba Vuong, Loc Bao Sang, BV 699 (VNM) . VIETNAM, Gia Lai Province, Kon Chu Rang Nature Reserve, 1 June 2016, M . Nuraliev, Nuraliev 1618 (LE01055514 http://en.herbariumle.ru/?t=occ&id=7269) . VIETNAM, Quang Binh Province, Minh Hoa District, 29 July 2011, Nguyen Tien Hiep et al., CPC 3919 (LE01057819 http://en.herbariumle.ru/?t=occ&id=8320) . VIETNAM, Quang Binh Province, Minh Hoa District, 23 July 2011, Nguyen Tien Hiep et al., CPC 3657 (LE01057820, http://en.herbariumle.ru/?t=occ&id=15154) .