Bulbophylum sect. Cirhopetallum s. str. (Orchidaceae) in Vietnam with the description of a new species, B. thangii, and a new national record, B. fenestratum Author Truong, Ba Vuong 0000-0003-3452-8455 Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Cau Giay District, Ha Noi, Vietnam & Institute of Tropical Biology Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, Dist. 3, Ho Chi Minh City, Vietnam Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia & bavuong 2019 @ yahoo. com; https: // orcid. org / 0000 - 0003 - 3452 - 8455 bavuong2019@yahoo.com Author Averyanov, Leonid V. 0000-0001-8031-2925 av _ leonid @ mail. ru; https: // orcid. org / 0000 - 0001 - 8031 - 2925 av_leonid@mail.ru Author Maisak, Tatiana V. 0000-0001-5919-6755 tmaisak @ mail. ru; https: // orcid. org / 0000 - 0001 - 5919 - 6755 tmaisak@mail.ru Author Dang, Minh Quan 0000-0002-0613-8532 School of Education, Can Tho University, 3 / 2 Street, Ninh Kieu District, Can Tho City, Vietnam & dmquan @ ctu. edu. vn; https: // orcid. org / 0000 - 0002 - 0613 - 8532 dmquan@ctu.edu.vn Author Nguyen, Van Canh 0000-0001-9578-0342 Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh Duong Province, Vietnam & nguyenvancanh @ gmail. com; https: // orcid. org / 0000 - 0001 - 9578 - 0342 nguyenvancanh@gmail.com Author Amlser, Roland 0000-0001-5574-5374 Swiss-Orchid-Garden, Untermattstrasse 27, 8370 Sirnach, Switzerland & ra-orchid @ gmx. ch; https: // orcid. org / 0000 - 0001 - 5574 - 5374 ra-orchid@gmx.ch Author Nguyen, Quoc Bao Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Cau Giay District, Ha Noi, Vietnam & Institute of Tropical Biology Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, Dist. 3, Ho Chi Minh City, Vietnam Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia Author Dang, Van Son Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Cau Giay District, Ha Noi, Vietnam & Institute of Tropical Biology Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, Dist. 3, Ho Chi Minh City, Vietnam Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia text Phytotaxa 2023 2023-11-09 625 2 201 210 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.625.2.6/51279 journal article 278718 10.11646/phytotaxa.625.2.6 e157489b-3deb-4e1f-b166-ea736ccc515f 1179-3163 10150886 Bulbophyllum sect. Cirrhopetalum (Lindl.) Reichenbach (1861: 259) ≡ Cirrhopetalum Lindley (1830: 45 , 58), id. (1824 sub pl. 832), nom nud. Type :— C. thouarsii Lindley (1830: 58) , nom. illeg. (= B. longiflorum Thouars 1822 t. 98). 10 accepted species (Vermeulen 2015). In Vietnam 4 species (1 endemic). Key to species of Bulbophyllum sect. Cirrhopetallum s. str. in Vietnam 1 Dorsal sepal with long clavate seta, 5–8 mm long; petals papillose ..................................................................................................2 - Dorsal sepal with short, simple seta, less than 2 mm long; petals not papillose................................................................................3 2 Petal apex somewhat truncate, margin with few hairs only in apical part; lip auriculate, finely hairy at the base.............................. ................................................................................................................................................................................... 1. B. annamense - Petal apex acute, margin fimbriate throughout; lip simple, entirely glabrous.......................................................... 2. B. longiflorum 3 Lateral sepals finely papillose; petals shortly fimbriate at apex............................................................................... 3. B. fenestratum - Lateral sepals warty to colliculate; petals hardly denticulate or erose at apex.................................................................4. B. thangii