Bulbophyllum section Rhytionanthos (Orchidaceae) in Vietnam with description of new taxa and new national record 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 Averyanov, Leonid V. Author Dang, Van Son 0000-0001-8681-4141 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay District, Hanoi, Vietnam & Institute of Tropical Biology Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, District 3, Ho Chi Minh City, Vietnam & dvsonitb @ gmail. com; https: // orcid. org / 0000 - 0001 - 8681 - 4141 dvsonitb@gmail.com Author Maisak, Tatiana 0000-0001-5919-6755 Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia & tmaisak @ mail. ru; https: // orcid. org / 0000 - 0001 - 5919 - 6755 tmaisak@mail.ru Author Bui, Van Huong 0000-0002-6219-1055 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay District, Hanoi, Vietnam & Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet Road, Cau Giay District, Hanoi, Vietnam & bvhuong 90 @ gmail. com; https: // orcid. org / 0000 - 0002 - 6219 - 1055 bvhuong90@gmail.com Author Tu, Bao Ngan 0000-0001-6971-3111 The Faculty of Chemistry and Biology, University Grenoble Alpes & Department of Biosciences, University of Milan & baongan. botany @ gmail. com; https: // orcid. org / 0000 - 0001 - 6971 - 3111 baongan.botany@gmail.com Author Truong, Ba Vuong 0000-0003-3452-8455 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay District, Hanoi, Vietnam & Institute of Tropical Biology Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, District 3, Ho Chi Minh City, Vietnam & bavuong 2019 @ yahoo. com; https: // orcid. org / 0000 - 0003 - 3452 - 8455 bavuong2019@yahoo.com text Phytotaxa 2022 2022-01-11 530 3 257 270 journal article 2663 10.11646/phytotaxa.530.3.1 72c8c74a-e501-43e1-ab1e-d21ece04d26f 1179-3163 5835973 5. B. strigosum (Garay) Sieder & Kiehn (2009: 407) ( Fig. 2 ). ≡ Rhytionanthos strigosum Garay (1999: 311) . Type :— VIETNAM , N Vietnam without indication of locality, ex Hort. Botanical Garden of the University of Vienna , Anton Sider 250/92 , holotype : WU0063106 https://www.jacq.org/detail.php? ID =267211 photo!; isotype AMES00084913 not seen . Description :—Epiphytic creeping herb. Pseudobulbs 1-leaved, pale green, narrowly ovoid, oblique, 2–2.5 cm tall, tapering to the apex, growing close together, connected by semi-woody rhizome, 2.3–2.5 mm in diameter, young pseudobulbs covered by brown fibrous sheaths. Leaves green, slightly twisted, petiolate; petiole 2.3–3.7 cm long; leaf blade narrowly oblong, 10–13 cm long, 1.8–2.2 cm wide, obtuse, slightly unequally 2-lobed. Inflorescence subumbellate, arising from base of pseudobulbs, erect, slender, green, spotted with purple; peduncle ca. 14.5 cm long with 1 to 2 overlapping tubular bracts at base and 2 distant tubular bracts above; rachis 1.5–2 mm long, bears 4–5 flowers opening simultaneously; floral bracts 6–8 mm long; pedicel and ovary ca. 1.5 cm long, slightly curved. Flower pale yellow with many red dots, more dense on lateral sepals and less in median sepal, petals yellow, margin dark red, lip adaxially dark red mottled with white, adaxially with many red blotches. Median sepal narrowly ovate to ovate, concave, ca. 9 mm long, 4 mm wide, obtuse, margin shortly fimbriate; lateral sepals ca. 2.5 cm long, 4 mm wide (at base) apex cuspidate, upper and lower margin sparsely papillose, outer surface sparely proximally verrucose; twisted and free at base, upper and lower margin turning inward and connate from near base to apex, distally forming narrowing tube. Petals ovate, ca. 2.5 mm long, 2 mm wide, margin fimbriate, apex obtuse. Lip mobile, with white thin ligament connected with apex of column foot, simple, recurved, ligulate, ca. 5 mm long, ca. 1.7 mm wide, apex obtuse to rounded; margin densely papillose; at base adaxially grooved. Column ca. 2 mm tall, at front with triangular wings, column foot ca. 3 mm long, upcurved; stelidia slender, subulate, ca. 6 mm long, slightly upcurved, upper margin with truncate tooth, lower margin sometime finely erose; anther cap rectangular in outline, ca. 1.2 mm long, with umbo at apex; pollinia 4, obovate, ca. 0.8 mm long. Fruit not seen. Habitat and phenology :—Evergreen broad-leaved forests at elevation about 1000 m a.s.l., rare. Branch epiphyte. Flowers at the end of May. Distribution :— Vietnam ( Lai Chau Province ). Endemic. Notes :—The specimens were found and collected in Sin Ho District, Lai Chau Province , and later were cultivated in private garden in Da Lat Town. Fimbriate median sepal, lateral sepals turning inwards with adnate upper and lower margins, shortly fimbriate free part of upper margin, fimbriate petals, and densely papillose lip are key characters of this species. Studied specimen :— VIETNAM , herbarium specimens prepared on 30 May 2021 by Truong Ba Vuong , Dang Van Son , Nghiem Xuan Son , BV 1255 ( VNM00069914 ), BV 1256 ( VNM00069915 ) from plants cultivated in Lam Dong Province , Da Lat Town , originated from Lai Chau Province , Sin Ho District , forest around Sin Ho Town .