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 10.11646/phytotaxa.625.2.6 1179-3163 10150886 2. Bulbophyllum longiflorum Thouars (1822: 98) , Seidenfaden (1973: 126); Vermeulen et al. (2015: 74). Type:— MADAGASCAR . Du Petit-Thouars L . M . A . 36 ( Holotype , photo P00097805 !) ( Fig. 2 ) FIGURE 2. Bulbophyllum longiflorum . A. Flowering plant. B & C. Inflorescence. D. Floral bract. E. Flower, half-side view and view from back. F. Dorsal sepal, abaxial and adaxial side. G. Lateral sepals, adaxial and abaxial side. H. Petals, abaxial and adaxial side. I. Magnified abaxial surface of petal. J. Lip, views from different sides. K. Ovary, petals and column, side view. L. Pedicel, ovary, and column, side view. M. Ovary, column, and lip, side view. N. Column, view from above. O. column apex, front view. P. Anther cap, view from below and from above. All photo by Truong Ba Vuong from specimen BV 1222 , photo correction and design by L. Averyanov and T. Maisak. ≡ Cirrhopetalum longiflorum (Thouars) Schlechter (1915: 420) . ≡ Phyllorchis longiflora (Thouars) Kuntze (1891: 675) . The other synonyms of this species are available online in Govaerts et al. (2023) (excluding Bulbophyllum eberhardtii (Gagnep.) Seidenfaden (1992: 285) . Habitat and phenology: —Epiphyte on tree trunks or branches in evergreen forest at elevation of 600–900 m a.s.l. Flowers in May–June. Distribution :— Vietnam (provinces Gia Lai , Kon Tum , Phu Yen ), East Africa, Madagascar , Mauritius , Reunion , Seychelles , Myanmar , Thailand , Vietnam , the Philippines , Peninsular Malaysia , Sulawesi, Sumatra, Java, Borneo, New Caledonia , New Guinea , Queensland. Conservation assessment: — Bulbophyllum longiflorum is a very popular species in the orchid trade. It is distributed widely in the tropical zones of Africa, Australia , and Asia (POWO 2023). In Vietnam , it is reported from three provinces that generate the extent of occurrence and the area of occupancy of 5008131 km 2 and 48 km 2 , respectively. In nature, plants are highly threatened due to collection for sale, deforestation, and habitat loss, which provide clear evidence of the wide decline in the number of individuals and the quality of their habitat. The total number of mature individuals and the generation length of the species are not known. Populations of this orchid known currently in three provinces are located wide apart from each other and highly fragmented. Hence, the threat does not affect them simultaneously but may be very serious for many local populations. Accordingly, the 12 sites known for this species are considered as 12 locations. Based on available information, the species can be preliminarily assessed as near threatened, NT B2b(iii,v) for Vietnam . Although the species is widespread, it is not yet found in the countries adjacent to Vietnam , so the present assessment may be true for all of Eastern Indochina. Note: —In our opinion, Bulbophyllum eberhardtii (Gagnep.) Seidenfaden (1992: 285) ( ≡ Cirrhopetalum eberhardtii Gagnepain 1931: 4 ) was erroneously treated as a synonym of B. longiflorum by Averyanov & Averyanova (2003) , followed by Govaerts et al. 2023 ). Based on the data of the protologue (“… Je ne puis que la comparer au C. ochraceum Ridley …” and the authentic color drawing of Eberhardt №21 (MNHN), with the Gagnepain handwritten note, “Forêts qui précèdent le plateau de Langbian vers 1300 mètres”, we assume that B. eberhardtii should belong to the section Ephippium ( Blume 1825: 308 ) Schlechter (1913: 700) instead of section Cirrhopetalum s.str. Within this section, it may be most closely related to Bulbophyllum tseanum (Hu & Barreto 1976: 30) Tsi (1999: 239) . More materials from the locus classicus area will be able to clarify the actual status and taxonomic position of this still rather ambiguous taxon. Specimens examined : VIETNAM : Gia Lai Province , 1985, Averyanov et al., LX-VN 2061a (photo LE01055746 https://en.herbariumle.ru/?t=occ&id=7629); 1985, Averyanov et al. LX-VN 2061a (photo LE01055745 https:// en.herbariumle.ru/?t=occ&id=7402); 1985, Averyanov et al. LX-VN2055 (photo LE01055744 https://en.herbariumle.ru/?t=occ&id=7401); 1985, Averyanov et al. LX-VN2084 (photo LE01055735https://en.herbariumle.ru/?t=occ&id=7392); 1985, Averyanov et al. LX-VN 0/205 (photo LE01055733 https://en.herbariumle.ru/?t=occ&id=7391); 1985, Averyanov CPB 85–205 157 , photo LE01055734 https://en.herbariumle.ru/?t=occ&id=15094); Province, 1989, Averyanov LX-VN 2000 (127) (photo LE 01055729 https://en.herbariumle.ru/?t=occ&id=7387); 1989, Averyanov et al. LX-VN 4261 (photo LE 01055731 https://en.herbariumle.ru/?t=occ&id=7389); 1989, Averyanov et al. LX-VN 4140 (photo LE01055732 https://en.herbariumle.ru/?t=occ&id=7390); 2021, Truong Ba Vuong & Ngo Quang Dang BV 1219 (VNM, analytical photos LE01124300 https://en.herbariumle.ru/?t=occ&id=186071); 2017, Nuraliev 1793 (photo LE01055724 https:// en.herbariumle.ru/?t=occ&id=7383). Kon Tum 2016, Nuraliev 1683 (photo LE 01055725 https://en.herbariumle.ru/?t=occ&id=7384); 2021, Truong Ba Vuong & Nghiem Xuan Son BV 1240 (VNM). Phu Yen Province , 2021, Truong Ba Vuong BV 1222 (VNM).