taxonID	type	description	language	source
03A0E6426E71357EFF35FF48DF96092E.taxon	description	(Fig. 1)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	diagnosis	Diagnosis: — Hemipilia uniflora differs from its congeners in inflorescence bearing predominantly 1 flower, peduncle and ovary densely papillose pubescent, and lip deeply dissected into 3 obtriangular lobes dentate at truncate apex.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	materials_examined	Type: — VIETNAM. Ha Giang Province: Quan Ba District, Bat Dai Son Nature Reserve, Thanh Van Commune, Mo Sai Village, around point 23 º 07 ʹ 46.4 ʺN 104 º 57 ʹ 56.2 ʺE, at elevation of 1000 – 1190 m a. s. l., karstic, highly eroded mountains composed of solid marble-like limestone, primary evergreen broad-leaved and mixed (with Pseudotsuga sinensis) humid forest on steep rocky slopes near mountain tops, miniature terrestrial tuberiferous herb, 3 April 2024, Bui Hong Quang, Nguyen The Cuong, Khang Sinh Nguyen, Tran Duc Binh, BHQ 1019 (holotype HN, isotype LE: LE 01277493 https: // en. herbariumle. ru /? t = occ & id = 248283, photos of plants used for preparation of the type specimen LE: LE 01255154 https: // en. herbariumle. ru /? t = occ & id = 228656, LE 01255208 https: // en. herbariumle. ru /? t = occ & id = 241360).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	description	Description: — Herb miniature, terrestrial, tuberiferous, rootless, glabrous. Tuber underground sub-globular, ovoid, or shortly cylindrical, pale yellowish to light brownish, (4) 5 – 8 (9) mm long, densely covered with soft white root hairs; tuber of the next generation developing at the base of stem. Stem arising from tuber, oblique to erect, (2.8) 3 – 5 (5.5) cm tall, terete, (0.8 –) 1 (– 1.2) mm in diameter, white at base, light pink to light greenish, finely speckled with dull purple, at base with 1 – 2 (3) tubular, white or light greenish acute bracts (3) 3.5 – 8 (10) mm long and 1.2 – 1.4 mm wide (when flattened) and 1 horizontally recurved cauline leaf. Leaf sessile, broadly lanceolate to narrowly ovate, often slightly falcate, conduplicate, adaxially rich green, abaxially light greenish to almost white, heavily speckled with brownish purple on both sides, (1.4) 1.6 – 2.6 (3) cm long, (5) 6 – 10 (11) mm wide, tapering from wide base to acute apex, with prominent median vein. Inflorescence predominantly uniflorous, rarely spike-like with 2 flowers; peduncle ebracteate, light pink to greenish, finely speckled with dull purple, (1.8) 2 – 3 (3.2) cm long densely papillose pubescent. Floral bracts erect, triangular, light greenish, (1.5) 2 – 3 (3.5) mm long, (0.6) 0.8 – 1.2 (1.4) mm wide, tapering from broad base to acute apex. Ovary terete, erect, somewhat curved, longitudinally ribbed, greenish, tinged with brownish purple, 8 – 9 mm long, 0.6 – 0.8 mm in diameter, densely papillose pubescent. Flowers usually solitary, rarely two, distant on 1.5 – 2 (3) mm, sessile, resupinate, widely opening, pink to light purple with purple spots on lip center, (4.6) 5 (5.4) mm across. Median sepal erect, 1 - veined, rectangular oblong, cymbiform, (3.8) 4 (4.2) mm long, (1.8) 2 (2.2) mm wide (when flattened), obscurely truncate and cucullate at apex, forming with petals hood, embracing column from above. Lateral sepals reflexed or recurved, straight, 1 - veined, obliquely oblong narrowly ovate, (4.6) 5 (5.4) mm long, (1.8) 2 (2.2) mm wide, obtuse to truncate at apex. Petals forward directed, without distinct veins, obliquely obovate, narrowing to the base, slightly concave, (2.8) 3 (3.2) mm long, (2.4) 2.5 (2.6) mm wide, round at apex. Lip downwards directed, spurred, deltoid in outline, without ornamentation, almost flat, finely papillulate, (8) 8.5 – 9 (9.5) mm long, (9.5) 10 – 10.5 (11) mm wide, deeply dissected to 3 lobes; lobes subequal, obtriangular, 4.5 – 5 mm long, (1.8) 2 (2.2) mm wide proximally, distally broadening to (3.8) 4 (4.2) mm wide, truncate and irregularly dentate at apex; spur at broad angle to lip, down directed, straight, narrowly clavate, obtuse and slightly dorsi-ventrally flattened at apex, as long or little shorter as ovary, 7 – 8 mm long, about 0.4 mm in diameter at the base, broadening to 1.6 – 1.8 mm wide at apex. Column erect, stout, obscurely half-globular, 1 – 1.2 mm tall and wide; anther erect, with 2 separate, close, parallel thecae narrowing (but not extending) at base and embracing caudicles; viscidia 2, separate, naked or covered by individual early agglutinated bursicle; rostellum in form of small, insignificant fold placed at the base of anther between viscidia; auricles small, finely verruculose; stigma entire, slightly concave placed below rostellum, facing to almost circular spur entrance. Pollinaria 2, very small, clavate, with short caudicle and almost circular viscidium. Fruits not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	etymology	Etymology: — The species name refers predominantly uniflorous inflorescence.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	biology_ecology	Ecology and phenology: — Primary evergreen broad-leaved and mixed (with Pseudotsuga sinensis) humid forest on highly eroded, solid marble-like limestone at elevation of 1000 – 1200 m a. s. l., commonly on steep rocky slopes near mountain tops. Flowers in February – April.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E71357EFF35FF48DF96092E.taxon	distribution	Distribution: — VIETNAM (Ha Giang Province, Quan Ba district, Bat Dai Son Nature Reserve). Endemic of Bat Dai Son Mountains. Conservation status: — Hemipilia uniflora is known from a single location with an Area of Occupancy (AOO) of less than 10 km 2. Owing to extensive selected logging in this area which is inferred as continuing decline of habitat, this species is assessed globally as Critically Endangered [CR B 2 ab (iii)] following the formal criteria proposed by the IUCN (2024). Notes: — Curiously our discovered plant fits in a series of morphological characters with recently segregated genus Sirindhornia H. A. Pedersen & Suksathan (Pedersen et al. 2003: 393) distributed in E Myanmar (Shan State), SW China (Yunnan), and NW Thailand (Tak & Chiang Mai provinces). Like three known species of Sirindhornia, our plant has stem and ovary densely papillose pubescent, one prostrate leaf heavily speckled with brownish purple spots, minute scarious floral bracts much shorter than ovary, sessile resupinate pink flowers, spurred 3 - lobed lip, small, hardly visible, fold-like rostellum placed between close thecae having no extensions, entire concave stigma, and 2 clavate separate pollinia. It is remarkable that the column structure of our plant looks almost identical with those figured on the Kerr hand drawing on the herbarium sheet Kerr 474 (K K 000595756) of the paratype of the type species of the genus. These drawings are dramatically different from figures illustrated the genus protologue (Pedersen et al. 2003, fig. 396, fig. 3) repeated later in the genus assessment (Pedersen et al. 2014: 263, fig. 154). Actually, our discovered plant together with all recognized species of Sirindhornia is surely very close to the genus Chusua Nevski (1935: 670), Orchis Linne (1753: 939), Ponerorchis Reichenbach (1852: 227), and Tsaiorchis Tang & Wang (1936: 131) in all basic morphological characters. In this connection, the segregation of Sirindhornia remains very questionable. Two other closest allies, Hemipilia Lindley (1835: 296) and Amitostigma Schlechter (1919: 91) differs from Sirindhornia, Chusua, Orchis, Ponerorchis, and Tsaiorchis alliance in the broad prominent rostellum (Hemipilia) and in very short pollinarium caudicles with naked separate viscidia (Amitostigma). It may be noted that the more or less acceptable morphological delimitation of mentioned genera s. str. does not entirely fit with clades identified by molecular cladistics (Tang et al. 2015, Jin et al. 2017) tentatively applied to the alliance taxonomy. In fact, according to its morphology Hemipilia uniflora shows unclear generic position between Sirindhornia, Hemipilia, and Ponerorchis having such characters as papillose hairy peduncle and ovary (typical for Sirindhornia), one leaf speckled with purple (common in Hemipilia), and parallel thecae, closely allied each other with very narrow connective (usual in Ponerorchis). Further molecular study of our plant may bring evidence that Sirindhornia clade based on study of a single species, Sirindhornia pulchella H. A. Pedersen & Indham. in Pedersen et al. (2003: 398), does not form too isolated clade, sister to the clade formed by Ponerorchis, Hemipilia and related genera (Jin et al. 2014, 2017, Tang et al. 2015). Meanwhile, our discovered plant before more detailed studies may be tentatively regarded as a member of the genus Hemipilia sensu lato.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E77357CFF35FAC8DC3D0F57.taxon	materials_examined	Type: — CHINA. Taiwan: Taipei, Mt. Pataoerh, February 25, 1979, Lin 435 (holotype TAIF, fide Lin et al. 2016: 99).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E77357CFF35FAC8DC3D0F57.taxon	biology_ecology	Ecology and phenology (in Vietnam): — Achlorophyllous mycoheterotrophic tuberiferous herb. Lowland evergreen broad-leaved closed forests on stratified solid shale, commonly along streams, at elevations of about 100 m a. s. l. Flowers in November – December.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E77357CFF35FAC8DC3D0F57.taxon	distribution	Distribution: — Vietnam (Quang Tri Province, Da Krong District). Japan, China (Taiwan). Conservation status: — Gastrodia fontinalis is presently known from a single location with one population in lowland area of Quang Tri Province (Da Krong District). This area has no official protection and experienced the wide uncontrolled anthropogenic transformation, resulting in decline in quality of the habitat. The AOO is less than 10 km 2. Owing to the fact that this is a mycoheterotrophic species and based on threat of ongoing decline in quality of habitat, the species can be assessed as Critically Endangered [CR B 2 ab (iii)] following formal criteria proposed by the IUCN (2024). The species is known to occur in Taiwan and Japan. Hence, due to such disjunct distribution range, the immigration of propagules from these countries is highly unlikely. In Japan this is considered as a very rare species (Suetsugu et al. 2014). Accordingly, the preliminary assessment of CR is retained for the final regional assessment of this species for Vietnam. Notes: — Plants discovered in central Vietnam (in Quang Tri Province) in their morphology fit well with Taiwanese plants described under the name Gastrodia fontinalis (Lin 1987). We have no doubts in their identification. Similar plants were discovered recently also from the Ryukyu Islands of southern Japan (Suetsugu et al. 2014). Both discoveries outside Taiwan anticipate a wide distribution of this unattractive achlorophyllous species, which was previously considered as a strict Taiwanese endemic. The location of the species, which was unexpectedly found in Vietnam, is more than 1500 km on the west-south-west from locus classicus and exhibits a significant ocean disjunction. Meanwhile, Vietnamese plants differ from Taiwanese specimens by not spreading perianth (vs. spreading perianth) and raceme-like inflorescence (vs. head-like inflorescence), and may represent local mainland race.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E77357CFF35FAC8DC3D0F57.taxon	materials_examined	Studied specimens: — VIETNAM, Quang Tri Province, Da Krong District, Trieu Nguyen Commune, lowland evergreen broad-leaved closed forest on stratified solid shale, along stream, around point 16 ° 40 ’ 33.9 ” N 106 ° 59 ’ 14.7 ” E, at elevation about 100 m a. s. l., 8 December 2023, Tuan Anh Le, AL 2808 (analytical photos LE: LE 01124749 https: // en. herbariumle. ru /? t = occ & id = 208857).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E75357CFF35FD08DB3E0AD2.taxon	materials_examined	Type: — SINGAPORE. Cult. Loddiges sine num. (holotype K 000079266 photo!).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E75357CFF35FD08DB3E0AD2.taxon	biology_ecology	Ecology and phenology (in Vietnam): — Trunk and branch epiphyte. Evergreen broad-leaved forests on granite at elevation of 1300 – 1500 m a. s. l. Flowers in April – May.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E75357CFF35FD08DB3E0AD2.taxon	distribution	Distribution: — Vietnam (Lam Dong Province, Lam Ha District). Thailand, Laos, Peninsular Malaysia, Singapore, Sumatra, Borneo. Conservation status: — According to currently available data, Coelogyne cumingii occurs at several sites in Vietnam in the northern part of Lam Ha District (Lam Dong Province) allied to Bidoup Nui Ba National Park. The area and extent of occurrence can’t be accurately estimated. This area has no official protection and currently experiencing wide anthropogenic pressure like development, agriculture and uncontrolled deforestation leading to decline in the quality of habitat. Hence, the species can only be assessed as Data Deficient (DD) based on current state of knowledge in Vietnam. The species is widespread and occurs in Borneo, Laos, Malaya, Sumatera, Thailand. And, it was reported as a very common plant in some locations of Peninsular Malaysia (Seidenfaden & Wood 1992). Notes: — The discovery of this species in Lam Dong Province of southern Vietnam is predictable, as it was reported earlier from Champassak Province of southern Laos (Schuiteman et al. 2008), placed about 400 km to the north-west from discovered Vietnamese locations. The morphology of the plants found in Vietnam fits in almost all characters with specimens from main area of the species distribution. The record of C. cumingii from Myanmar (Tun 2014: 115) is regarded to be wrong (Ormerod et al. 2021: 74), belonging in fact to C. schultesii S. K. Jain & S. Das (1978: 121). Coelogyne cumingii also was speculatively recorded from Vietnam (Schuiteman et al. 2008, POWO 2024). We have not seen any verified specimens that confirm these records.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E75357CFF35FD08DB3E0AD2.taxon	materials_examined	Studied specimens: — VIETNAM, Lam Dong Province, Lam Ha District, evergreen broad-leaved forest on granite at elevation of 1300 – 1500 m a. s. l., herbarium prepared from cultivated plants, 11 May 2024, L. Averyanov, Nguyen Van Canh, T. Maisak, AL 3151, flowers white, lip with very light lemon center (LE: LE 01276681 https: // en. herbariumle. ru /? t = occ & id = 235145, photos of plant used for preparation of voucher specimen LE 01255032 https: // en. herbariumle. ru /? t = occ & id = 228072). VIETNAM, Lam Dong Province area, plant obtained from local collectors, photos and herbarium prepared in 12 May 2024, L. Averyanov, Nguyen Van Canh, T. Maisak, AL 3188 (LE: LE 01276680 https: // en. herbariumle. ru /? t = occ & id = 235144, LE 01276679 https: // en. herbariumle. ru /? t = occ & id = 235143, photos of plant used for preparation of voucher specimen LE 01255068 https: // en. herbariumle. ru /? t = occ & id = 228108).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	description	(Fig. 4.)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	diagnosis	Diagnosis: — The new species differs from the morphologically closest C. eburneum and C. maguanense in insignificant narrowly fusiform pseudobulbs 1.6 – 3 cm long, linear leaves 4 – 6.5 mm wide, peduncle 8 – 14 cm long, smaller flowers with yellowish green sepals 4 – 4.6 cm, glabrous lip 3.2 – 4 cm long, narrow petals 5 – 7 mm wide, median lip lobe triangular cordate, 9.5 – 11.5 mm long and wide, disk with low fleshy longitudinal keel obscurely 4 - dentate at apex, column 3.2 – 3.4 cm tall, densely hairy at front in basal third.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	materials_examined	Type: — VIETNAM. Type herbarium specimen was prepared from cultivated plants on 22 August 2023, L. Averyanov, Nguyen Van Canh, T. Maisak, AL 2241 (holotype LE: LE 01232953 https: // en. herbariumle. ru /? t = occ & id = 192246, isotype LE 01232954 https: // en. herbariumle. ru /? t = occ & id = 192247), originally collected in Dak Lak Province, Chu Yang Sin National Park, Chu Yang Sin Mt., primary broad-leaved evergreen forest at elevation of 1600 – 1700 m a. s. l., epiphyte on tall mossy tree, not common. August 2019, Nguyen Van Canh s. n., photos of plants used for preparation of the type specimen (LE: LE 01124312 https: // en. herbariumle. ru /? t = occ & id = 186936, LE 01124313 https: // en. herbariumle. ru /? t = occ & id = 1869370, LE 01255215 https: // en. herbariumle. ru /? t = occ & id = 241569).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	description	Description: — Epiphytic or lithophytic herb with densely clustering pseudobulbs. Pseudobulbs narrowly fusiform, often slightly flattened, (1.6) 2 – 2.6 (3) cm long, (0.8) 0.9 – 1.2 (1.4) cm wide, entirely covered by leaf sheaths, at base with 2 – 3 subulate, brownish purple, coriaceous, acute cataphylls, (1.2) 1.6 – 3.2 (3.8) cm long, 10 – 2.5 mm wide (when flat). Roots thick, fleshy, white to yellowish brown, 3 – 3.5 mm in diameter. Leaves (3) 4 – 8 (9), articulate, base distichous, linear, arching, to (15) 20 – 40 (45) cm long, (4) 4.5 – 6 (6.5) mm wide, acute. Inflorescence arising from base of pseudobulb, ascending to erect; peduncle (8) 10 – 12 (14) cm long, at base with (3) 4 (5) reddish brown, imbricate, conduplicate, cymbiform, acute bracts, at apex with 1 – 2 flowers opening simultaneously. Floral bracts pale green, triangular, 3.2 – 3.4 mm long and wide, acute. Pedicel and ovary pale yellowish to dull pink, terete, narrowly obconoid, 2.2 – 2.6 cm long, 2.8 – 3.2 mm in diameter. Flowers not widely opening, (2.2) 2.5 – 3 (3.2) cm in diameter; petals and sepals light yellowish green with pink tint in basal half, obtuse to acute; lip uniform rose pink with light greenish center, callus distally white; column white tinged pale pink, light yellow at front near the base. Sepals straight, forward directed, broadly oblanceolate, obtuse, (4) 4.2 – 4.4 (4.6) cm long, (8) 9 – 11 (12) mm wide, lateral sepals oblique. Petals oblanceolate, oblique, acute, as long as sepals, (5) 5.5 – 6.5 (7) mm wide. Lip obtriangular to obovate in outline, (3.2) 3.5 – 3.8 (4) cm long, 1.8 – 2.2 cm wide, 3 lobed, at base fused to basal margins of column for 5.5 – 6.5 mm; loosely clasping column, side lobes erect, half-ovate, 1.8 – 2 cm long, 7 – 8 mm wide, apex rounded; median lobe triangular cordate, undulate along the margin, (9.5) 10 – 11 (11.5) mm long and wide, obtuse to rounded at apex, strongly recurved to revolute; disk glabrous to finely papillate, with low fleshy longitudinal keel 4.5 – 5 mm wide, extending from base of lip to base of median lobe, at apex obscurely 4 - dentate. Column erect, at apex slightly forward curved, 3.2 – 3.4 cm tall, 4.5 – 5.5 mm wide, narrowly winged, in basal third at front with concave area densely hairy with long white hairs; stigma obscurely obtriangular. Operculum helmet-shaped, glossy glabrous, at front with very short, broad beak. Pollinia 2, ovoid, with short, broad, common caudicle and viscidium. Fruits not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	etymology	Etymology: — The species is named by L. Averyanov and Nguyen Van Canh after Mr. Truong Ba Vuong, a distinguished expert in the taxonomy of orchids in eastern Indochina. data from personal observations, as well as Lindley 1847, Liu 1996, Pearce & Cribb 2002, Liu et al. 2006, and Chen et al. 2009).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	biology_ecology	Ecology and phenology: — Epiphyte or lithophyte, primary broad-leaved evergreen submontane and montane forests on granite at elevation of 1600 – 1700 m a. s. l. Flowers in cultivation in August – September.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	distribution	Distribution: — Vietnam, Dak Lak Province (Chu Yang Sin National Park). Probably endemic of Central Highlands in southern Vietnam. Conservation status: — This species is known from a single site by a single extremely small population. This population discovered in Chu Yang Sin National Park includes few mature samples. The AOO is less than 10 km 2. Despite official protection of the territory harboring a single species population, it is still influenced by selective logging and a decrease in habitat quality. This is inferred as continuing decline in quality of habitat. The number of locations is one accordingly. Additionally, taking into consideration the high demands for the Cymbidium species on the market of wild ornamental plants, this species need to be protected. Accordingly, following the formal criteria of the IUCN Red List (2024), it is assessed as Critically Endangered (CR) B 2 ab (iii). Notes: — In plant habit and floral morphology Cymbidium bavuongii is most close to C. eburneum Lindley (1847 tab. 67) and C. maguanense Liu (1996: 412), but differs in a series of characters listed in details in Table 1.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E7B3571FF35FC90DFED0CA6.taxon	materials_examined	Additionally studied specimens (paratypes): — VIETNAM. Dak Lak Province, Cu D’Ram Commune, Krong Bong District, Chu Yan Sin Mountain, 28 August 2023, Truong Ba Vuong, Loc Bao Sang, BV 1901 (VNM 00070007), BV 1902 (VNM 00070009), photos of plants used for the preparation of paratypes LE (LE 01255145 https: // en. herbariumle. ru /? t = occ & id = 228647).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E783571FF35FE34DA7208FE.taxon	materials_examined	Type: — NEPAL. Buchanan-Hamilton s. n. (holotype BM BM 000525392 photo!).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E783571FF35FE34DA7208FE.taxon	biology_ecology	Ecology and phenology (in Vietnam): — Terrestrial tuberiferous herb. Open grasslands among dry semideciduous Dipterocarp forest at elevation ca. 500 m a. s. l. Flowers in March – April.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E783571FF35FE34DA7208FE.taxon	distribution	Distribution: — Vietnam (Dak Lak Province, Ea Hleo District). Nepal, NE India, Bangladesh, Myanmar, China (Hainan), Thailand, Peninsular Malaysia, Sumatra, Java, the Philippines, New Guinea, Australia. Conservation status: — According to currently available data Eulophia bocallosa is extremely rare plant in Vietnam known by the only collection. Nothing is known about the population and ecology of this species in Vietnam or outside where this species is distributed, namely, from India, to China through Indochina to Indonesia and Australia. This species is mentioned as an extremely rare, highly endangered plant in Sumatra and Java (Comber 1990, 2001). Accordingly, this species can only be assessed as Data Deficient (DD) for Vietnam. Further field studies are necessary for understanding the distribution range of this species. Notes: — The discovery of this widespread species in Vietnam is predictable and not surprising. However, it is the first it’s record in eastern Indochina, including mainland China, Laos, and Cambodia. The plant has ephemeral mode of life (surviving during dry season in form of leafless underground tuber) and may be easily overlooked during botanical surveys in the dry, rainless season.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E783571FF35FE34DA7208FE.taxon	materials_examined	Studied specimens: — VIETNAM, Dak Lak Province, Ea Hleo District, grassland, at elevation of 400 – 500 m a. s. l., photos of 28 March 2023, Nguyen Van Canh, AL 2221 (LE: LE 01124265 https: // en. herbariumle. ru /? t = occ & id = 180620, LE 01255216 https: // en. herbariumle. ru /? t = occ & id = 241570); grassland in Dipterocarp forest, April 2023, Nguyen Van Canh, AL 2447 (LE: LE 01253859 https: // en. herbariumle. ru /? t = occ & id = 213839).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	description	(Fig. 6 & 7)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	materials_examined	Type: — MALAYSIA. Central Java & Djokjakarta, “ Java: Tegal (Raciborski); Djokjakarta (Raciborski) ” (Schechter in Smith 1905: 552). Syntypes destroyed in B (fide Wood & Cribb 1994: 366). Possible (questionable) isosyntype in Harvard University Herbaria (AMES 00106675).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	description	Description (based on specimens from Vietnam): — Herb monopodial, miniature, epiphytic, glabrous. Stem (0.8) 1 – 1.6 (1.8) cm long, completely covered by distichous leaf sheaths, slightly flattened, with many pale green wiry roots clustered near stem base. Leaves (5) 6 – 9 (10), sessile, jointed, obliquely lanceolate, falcate, (3.5) 4 – 6 (7) cm long, (4) 5 – 7 (8) mm wide, apex with two obtuse oblique unequal lobes. Inflorescence axillary, subdense, head-like raceme, down directed, glabrous; peduncle straight, terete, (1) 1.1 – 1.3 (1.4) cm long, with (1) 2 – 3 (4) distant sterile narrowly triangular subacute bracts, (0.8) 1 – 1.2 (1.3) mm long, 0.5 – 0.7 mm wide; rachis (3) 3.5 – 4.5 (5) mm long, with several distichous triangular floral bracts; floral bracts close to each other, narrowly triangular, acute, sharp. persistent, (1) 1.2 – 1.3 (1.4) mm long, 0.5 – 0.6 mm wide; 1 – 4 (5) flowers blooming simultaneously; inflorescence developing for a long time and thus flowers occupy its apical half. Flowers opening during a few morning hours, shortly fugacious, resupinate. Pedicel and ovary light green, glabrous, terete, shallowly 6 - grooved, suberect, straight or slightly recurved, (2) 2.2 – 2.6 (2.8) mm long, 0.4 – 0.5 mm in diameter. Sepals free, subequal, broadly lanceolate, acuminate, tapering from broad base to the apex, straight, (6.4) 6.6 – 7 (7.2) mm long, (1.4) 1.5 (1.6) mm wide near the base, light yellowish with yellow apical third. Petals narrowly triangular or broadly lanceolate, acute, straight, as broad as sepals but twice shorter, light yellowish with yellow apical third. Lip simple, triangular, trilobed, very fleshy, recurved, movably attached to the apex of column foot, lying almost parallel to column, (1.5) 1.6 (1.7) mm long and wide, entirely uniformly yellow; side lobes half-circular, suberect, very thin, (0.8) 0.9 – 1 (1.1) mm broad, 0.3 – 0.4 mm tall, entire or finely erose along the margin; median lobe conoid, fleshy, 0.6 – 0.7 mm long, obtuse to subacute; disc without ornamentation. Column erect, stout, white or white with light greenish tint, (0.7) 0.8 – 1 (1.1) mm tall and wide; stigma almost circular, concave; column foot free, forward directed, as long as column. Operculum helmet-shaped, (0.6) 0.7 (0.8) mm in diameter, with flat recurved margin, without beak. Pollinia 2, globular, 0.3 – 0.35 mm in diameter, entire or with a hardly visible cavity; stipe oblong, 0.2 – 0.25 mm long, viscidium half this size, ovate to almost circular. Fruit not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	biology_ecology	Ecology and phenology: — (in Vietnam) Monopodial canopy epiphyte. Primary evergreen broad-leaved submontane forests on karstic limestone at elevations of 800 – 1000 m a. s. l. Flowers in June – July.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	distribution	Distribution: — Vietnam (Son La Province, Thuan Chau District). Malacca Peninsula, Thailand?, Java, Borneo. Conservation status: — Biermannia brachystachys is presently known in Vietnam from a single site with one documented population. Nothing is known about the population and ecology of this species. Accordingly, this species can be assessed as Data Deficient (DD) for Vietnam. The species is known to be distributed in Borneo, Jawa and Thailand. Notes: — The genus Biermannia prior to this study included thirteen accepted species distributed from northeastern India and southern China through the Indochinese and Malay Peninsulas to Sumatra, Java and Borneo (Comber 1990, 2001, Seidenfaden & Wood 1992, Pearce & Cribb 2002, Rao 2006, Chen et al. 2009, Chase et al. 2015, Averyanov et al., 2018 a, b, Ding et al. 2019). All species of this genus are miniature, canopy epiphytes with small, unattractive fugacious flowers lasting only few hours in the morning. As a result, these orchids are easily overlooked in botanical surveys, poorly represented in herbaria and remain infrequently inventoried in local floras throughout its range. Vietnam seems to be an area of the highest species diversity of this genus with six earlier recorded species (Seidenfaden 1992, Averyanov 1994, Pham H. H. 2000, Averyanov & Averyanova 2003, Nguyen et al. 2005, Xu et al. 2010, Zhou et al. 2016, Averyanov et al., 2018 a, b) and two species reported additionally in this study.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E78356AFF35F924DA0B0F7A.taxon	description	Studied specimen: — VIETNAM, Son La Province: Thuan Chau District, Phong Lai Commune, Phieng Long Village, foots of Pha Din Pass area, remnants of primary evergreen broad-leaved forests on limestone mountains at elevation of 800 – 1000 m a. s. l., epiphytic perennial herbs, 5 July 2023, K. S. Nguyen & T. V. Lo, AL 2233 a (LE: LE 01276688 https: // en. herbariumle. ru /? t = occ & id = 235152, photos of plants used for preparation of the voucher specimen LE 01124273 https: // en. herbariumle. ru /? t = occ & id = 181365, LE 01255217 https: // en. herbariumle. ru /? t = occ & id = 241571, drawing LE 01255181 https: // en. herbariumle. ru /? t = occ & id = 234691).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	description	(Fig. 8)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	diagnosis	Diagnosis: — Biermannia averyanovii var. micrantha differs from the type of B. averyanovii in the twice smaller flowers with sepals less than 3 mm long, floral bracts ovate triangular, little longer than wide, pedicel and ovary less than 1.5 mm long, and lip median lobe laterally flattened, almost straight, less than 0.8 mm long.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	materials_examined	Type: — VIETNAM. Son La Province: Thuan Chau District, Phong Lai Commune, Phieng Long Village, foots of Pha Din Pass area, remnants of primary evergreen broad-leaved forests on limestone mountains at elevation of 800 – 1000 m a. s. l., 5 July 2023, K. S. Nguyen & T. V. Lo, AL 2233 b (holotype LE: LE 01276689 https: // en. herbariumle. ru /? t = occ & id = 235153, photos from plant used for the preparation of type specimens LE 01255179 https: // en. herbariumle. ru /? t = occ & id = 234689, drawing LE 01255180 https: // en. herbariumle. ru /? t = occ & id = 234690).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	description	Description: — Herb monopodial, miniature, epiphytic, glabrous. Stem (0.4) 0.6 – 1.2 (1.4) cm long, completely covered by distichous leaf sheaths, slightly flattened, with many pale green wiry roots clustered near stem base. Leaves (5) 6 – 8 (10), sessile, jointed, obliquely broadly lanceolate, (2) 2.5 – 4 (4.5) cm long, (4.5) 5 – 8 (10) mm wide, apex with two subacute oblique unequal lobes. Inflorescence, axillary, subdense, head-like raceme, erect, glabrous; peduncle straight, terete, (4.5) 5 – 6 (7) mm long, about 1 mm in diameter, with (1) 2 – 3 (4) close sterile triangular ovate, shortly acuminate bracts, (0.8) 1 – 1.2 (1.4) mm long, 0.6 – 0.8 mm wide; rachis somewhat inflated, (2.5) 3 – 5 (5.5) mm long, (1) 1.2 – 1.6 (1.8) mm in diameter, twice wider than peduncle, with many spirally arranged triangular floral bracts; floral bracts close to each other, triangular, sharp. persistent, (1.4) 1.6 – 1.8 (2) mm long, 0.8 – 1 mm wide, with acute, somewhat recurved apex; 1 – 4 (5) flowers blooming simultaneously; inflorescence developing for a long time and thus flowers occupy its apical half. Flowers opening during a few morning hours, shortly fugacious, resupinate. Pedicel and ovary light green, glabrous or with few scattered scurfy hairs, terete, shallowly 6 - grooved, suberect, straight or slightly recurved, (1.1) 1.2 – 1.4 (1.5) mm long, 0.3 – 0.35 mm in diameter. Sepals free, subequal, broadly lanceolate to narrowly ovate, acuminate, tapering from broad base to the apex, straight, (2.7) 2.8 – 2.9 (3) mm long, (0.7) 0.8 (0.9) mm wide near the base, uniformly light yellowish, slightly carinate outside. Petals narrowly triangular, acuminate, tapering from broad base to the apex, straight, (2.3) 2.4 – 2.6 (2.7) mm long, 0.7 – 0.8 mm wide, uniformly light yellowish. Lip simple, triangular ovate in outline, obscurely trilobed, with fleshy center and thin side lobes, almost straight, movably attached to the apex of column foot, lying almost parallel to column, (1.7) 1.8 – 2 (2.1) mm long, wide, 1.3 – 1.4 mm wide (when flattened), pale yellowish; side lobes half-circular, erect, very thin, (0.9) 1 (1.1) mm broad, 0.3 – 0.4 mm tall, entire or finely erose along the margin; median lobe fleshy, narrowly conoid, slightly laterally flattened, acuminate, straight, forward directed, 0.7 – 0.8 mm long; disc without ornamentation. Column erect, stout, (0.8) 1 (1.2) mm tall, 0.6 – 0.7 mm wide; stigma ovate to almost circular, concave; column foot free, forward directed, little shorter than column. Operculum cap-shaped, about 0.5 mm in diameter, with straight margin without beak. Pollinia 2, globular, 0.2 – 2.2 mm in diameter, entire or with a hardly visible cavity; stipe oblong, about 0.1 mm long, viscidium half this size, ovate. Fruit not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	etymology	Etymology: — The varietal epithet refers to the small size of flower particularly to this species.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	biology_ecology	Ecology and phenology: — Monopodial canopy epiphyte. Primary evergreen broad-leaved submontane forests on karstic limestone at elevations of 800 – 1000 m a. s. l. Flowers in June – July.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E633568FF35FD40DD970C12.taxon	distribution	Distribution: — Endemic to Son La Province (Thuan Chau District) thus far. Conservation status: — Biermannia averyanovii var. micrantha is presently known from a single site with one documented population. Nothing much is known about the ecology of this variety. Accordingly, it can be assessed as Data Deficient (DD) following formal criteria proposed by the IUCN (2024).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E61356FFF35FEF8DFED0E76.taxon	materials_examined	Type: — China. Yunnan: Xishuangbanna (Mengla), 20 June 1985, Z. H. Tsi 215 (holotype PE, photo!).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E61356FFF35FEF8DFED0E76.taxon	description	Description (based on Vietnamese plants): — Epiphytic monopodial glabrous (except some details of flower) herb. Stem pendulous, rather slender, terete, simple or few branching to 0.6 m long, (1.5) 2 (2.5) mm in diameter, with internodes (1.6) 2 – 3 (3.4) cm long and many distant vermiform, roots, which often thicker than the stem. Leaves sessile, dark green, recurved or somewhat flexuose, semi-terete, adaxially channeled, (8) 10 – 14 (16) cm long, (1.8) 2 – 2 (2.2) mm in diameter, with a persistent sheathing base, acute without constriction near apex. Inflorescence pendent, lax raceme or panicle with 1 – 2 branches, bearing totally to 20 flowers; peduncle, greenish, heavily mottled with brown purple, bearing (2) 3 – 4 (5) minute, triangular, distant, sterile bracts; rachis longitudinally irregularly ribbed, (2.5) 3 – 8 (9) cm long, 1 – 1.2 mm in diameter. Pedicel and ovary olive green flushed with purple brown, terete, (3.5) 4 – 6.5 (7) mm long, 0.6 – 0.8 (1) mm in diameter, longitudinally obscurely 6 - grooved. Flowers widely opening, (0.7) 0.8 – 1.2 (1.3) cm across; petals and sepals spreading to bent backwards, dull yellowish-green with pale reddish-brown spots, 3 - veined, with entire margin; lip light yellowish; anther cap yellow. Sepals subsimilar, narrowly obovate, (4.8) 5 – 5.2 (5.4) mm long, (2.4) 2.6 – 3 (3.2) mm wide, roundish at apex; median sepal slightly concave; lateral sepals slightly oblique, with strongly recurved margins. Petals narrowly obovate, slightly oblique, (3.8) 4 (4.2) mm long, (1.2) 1.4 – 1.8 (2) mm wide, roundish at apex, with somewhat recurved margins. Lip fleshy, 3 - lobed, spurred, (7.8) 8 – 9.2 (9.4) mm long from apex of spur to apex of median lobe, 3.4 – 3.6 mm wide, adaxially finely papillulate; lateral lobes triangular, forward directed, 1.5 – 2.5 mm long and wide, acute; each lobe inside near apex with an prominent finger-like or subulate incurved processus and a prominent incurved wing-like semicircular flap near the base; median lobe triangular sagittate, fleshy, 1.8 – 2 mm long, (2.6) 2.8 – 3.4 (3.6) mm wide, spreading forwards, with 2 prominent broad suborbicular calli on adaxial surface, at base constricted, apex truncate; spur oblong, 5 – 5.5 mm long, 2 – 2.2 mm wide, backward directed, dorsiventrally flattened, below with shallow longitudinal groove, almost round at apex, inside with prominent incomplete septum and inverted V-shaped callus on the back wall of spur. Column stout, shortly cylindric, (2.6) 2.8 – 3 (3.4) mm tall, 2.4 – 2.8 mm wide, wingless, at base finely hairy; rostellum insignificant, in form of 2 flap-shaped rudiments. Operculum helmet-shaped, half-globular, (1.2) 1.4 – 1.6 (1.8) mm in diameter, with prominent obscurely quadrate, forward directed beak, truncate and somewhat notched at apex. Pollinia 4, subsimilar, half-globular, arranged in 2 units, bright yellow, held on apex of erect caudicle perpendicular to viscidium; viscidium collar-shaped, 1 – 1.2 mm wide; caudicle oblong, conduplicate, attached to top of viscidium, 0.9 – 1.1 mm long, almost straight or slightly back curved. Fruit cylindrical, slightly curved, shortly stalked, longitudinally 6 - ridges capsule 1.7 – 2 cm long, 2 – 3 mm in diameter (not ripe).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E61356FFF35FEF8DFED0E76.taxon	biology_ecology	Ecology and phenology (in Vietnam): — Epiphyte on mossy trees. Evergreen broad-leaved submontane forests on rocky limestone at elevations of 1000 – 1200 m a. s. l., very rare. Flowers in June – July.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E61356FFF35FEF8DFED0E76.taxon	distribution	Distribution: — Vietnam (Son La Province, Thuan Chau District). China (Yunnan Province, Xishuangbanna autonomous prefecture). Conservation status: — Cleisostoma nangongense is presently known in Vietnam from a single location with one documented population, which area has no official protection and experienced currently the wide uncontrolled deforestation. This is inferred as continuing decline in quality of habitat. Based on the above information this species can be assessed as Critically Endangered B 2 ab (iii) following formal criteria proposed by the IUCN (2024). This species is also distributed in China where the conservation status is declared as Vulnerable (Jin et al. 2023). There are chances of immigration of propagules from adjacent areas in north, hence, the preliminary assessment of CR is downlisted to Endangered [EN B 2 ab (iii)] fore regional assessment in Vietnam. Notes: — Plants discovered in Vietnam almost entirely fit in their morphological characters with Cleisostoma nangongense described from SW Yunnan. Meanwhile, Vietnamese plant has entire, straight margin of sepals and petals in contrast of denticulate sepals and petals reported for Chinese plants (Tsi 1989, Chen et al. 2009, Jin et al. 2023). If this observation is true, Vietnamese plants should be regarded as a separate variety. From the other hand, Cleisostoma schoenorchaefolium Kumar & S. W. Gale in Kumar et al. (2018: 157, fig. 1 & 2) described from NW Laos (Type: — Lao PDR., Xayaboury Province: Parklai District, Mouang Pa Village, Pha Pheung Mountain, 30 June 2016, 455 m, Fischer, Kumar, Phaxaysombath & Sysouphanthong HNL-KFBG 0729) and regarded later as a synonym of C. nangongense (Kumar & Gale 2020) it seems is actually a separate taxon. It differs from plants found in China and Vietnam in a series of following distinct characters: leaves to 24 cm long (vs. leaves 8 – 17 cm long, leaf apex with a constriction 1 – 1.5 cm before the tip (vs. leaves have no constriction near apex), inflorescence raceme with up to 5 (vs. inflorescence raceme or panicle with up to 20 flowers), sepals acute, 6 – 7.5 mm long (vs. sepals round at apex, 4.8 – 5.4 mm long), petals 2 - veined, acute, 5 – 5.5 mm long (vs. petals 3 - veined, round at apex, 3.8 – 4.2 mm long), lip 7.5 – 8.5 mm long from tip of spur to tip of median lobe (vs. lip 8.6 – 9.4 mm long), each lateral lobe inside near apex, with an inconspicuous triangular appendage (vs. appendage in form of prominent finger-like or subulate incurved uncinate processus), median lobe 2 – 2.3 mm long, 2.5 – 3 mm wide, slightly notched at apex (vs. median lobe 1.8 – 2 mm long, 3.4 – 3.6 mm wide, truncate), spur slightly scrotiform at apex (vs. spur apex almost round at apex), column 2.5 mm long, 2.5 mm wide (vs. column 3.4 – 3.6 mm tall, 2.8 – 3.2 mm wide), pollinia inequal, each unit comprising one larger and one smaller pollinium (vs. pollinia subequal, half-globular), caudicle strongly bent back, terminated in a prominent pointed hood (vs. caudicle straight or hardly bent back, distally without a pointed hood). Both species differ from other congeners in sulcate leaves, but in floral morphology are very similar to C. chantaburiense Seidenfaden (1975: 70, fig. 31) and C. simondii (Gagnepain 1951: 628) Seidenfaden (1975: 66, fig. 30) that do not support the segregation of C. schoenorchaefolium and C. nangongense into separate section, C. sect. Teretisculum Kumar & S. W. Gale in Kumar et al. (2018: 156).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E61356FFF35FEF8DFED0E76.taxon	materials_examined	Studied specimens: — Vietnam, Son La Province: Thuan Chau District, Chieng Pac Commune, pendulous, epiphyte on trunks or branches, in rocky mountain, 9 July 2023, Truong Ba Vuong, Nguyen Quoc Bao, BV 1786 (LE: LE 01253790 https: // en. herbariumle. ru /? t = occ & id = 238798, LE 01276704 https: // en. herbariumle. ru /? t = occ & id = 238799, LE 01253789, https: // en. herbariumle. ru /? t = occ & id = 238797 photos from plants prior preparation of voucher herbarium specimens BV 1786 LE 01124283, https: // en. herbariumle. ru /? t = occ & id = 184044 LE 01255205 https: // en. herbariumle. ru /? t = occ & id = 239469).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	description	(Fig. 11 & 12)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	diagnosis	Diagnosis: — Cleisostoma truongquanii differs from morphologically closest C. dorsisacculatum in shorter leaves 4 – 7 cm long, inflorescence raceme or panicle with 1 – 5 branches, peduncle 3 – 4 cm long, twice smaller flowers 4 – 5.2 mm across, lip lobes without ornamentation, median lip lobe triangular sagittate, spur at entrance finely papillulate, inside without septum, and back-wall callus in form of very small, hardly visible pocket.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	materials_examined	Type: — VIETNAM. Kon Tum Province: the border area between Tu Mo Rong and Dak Glei districts, Ngoc Linh Mountains, evergreen broad-leaved forest on granite at elevation of about 1700 m a. s. l., 22 July 2023, Truong Ba Vuong, Nguyen Ta Ton, BV 1894. (holotype LE: LE 01277102 https: // en. herbariumle. ru /? t = occ & id = 242537, isotype LE 01276711 https: // en. herbariumle. ru /? t = occ & id = 238805, photos of plants used for preparation of herbarium type specimen LE: LE 01124284 https: // en. herbariumle. ru /? t = occ & id = 184043, LE 01255206 https: // en. herbariumle. ru /? t = occ & id = 237794).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	description	Description: — Epiphytic monopodial glabrous herb. Stem erect to suberect, rather stout, terete, simple or few branching near the base, to 15 – 25 cm long, (5.5) 6 – 7 (8) mm in diameter, with internodes (0.8) 1 – 1.6 (2.4) cm long and several vermiform roots near the base. Leaves sessile, dark green above, light green below, rigid, distinctly conduplicate, slightly recurved to almost straight, oblong lorate, (4) 4.5 – 6.5 (7) cm long, (0.8) 1 – 1.2 (1.4) cm wide, with a persistent, greenish or brownish purple sheathing base and apex with two subequal roundish lobes. Inflorescence arcuate, sub-lax raceme or few branching many-flowered panicle; peduncle, 3 – 4 (5) cm long, greenish, sometime with light purple tint, bearing (1) 2 – 3 minute, distant, triangular, sterile bracts; rachis longitudinally irregularly ribbed, to 6 (7) cm long, 1.2 – 1.4 mm in diameter; floral bracts triangular, insignificant, less than 1 mm long. Pedicel and ovary light green, slightly curved, terete, (1.8) 2 – 2.8 (3) mm long, about 0.5 – 0.7 mm in diameter, longitudinally obscurely 6 - grooved. Flowers widely opening, (4) 4.2 – 5 (5.2) mm across; petals and sepals spreading, orange brown to purple brown with dull yellow margin, with entire margin; lip white with purple side; column light yellow with purple base, anther cap white to yellowish. Sepals subsimilar, 3 - nerved, narrowly ovate to ovate, (2) 2.2 – 2.5 (2.7) mm long, (1.2) 1.4 – 1.8 (2) mm wide, obtuse; median sepal slightly concave, cucullate; lateral sepals slightly oblique. Petals narrowly oblong ovate, slightly oblique, (1.7) 1.8 – 2 (2.1) mm long, 0.8 – 1 mm wide, obtuse, almost flat. Lip fleshy, 3 - lobed, spurred, (3.4) 3.8 – 4.2 (4.5) mm long from apex of spur to apex of median lobe, (1.4) 1.6 – 1.8 (2) mm wide; side lobes triangular, forward directed, (0.9) 1 (1.1) mm long and wide, acute; inside flat, without ornamentation; median lobe triangular sagittate, fleshy, 1.9 – 2 mm long and wide; side lobules acute, back directed; median lobule roundish to truncate, forward directed; spur obovoid saccate, 2 – 2.5 mm long, 1.8 – 2 mm wide, inside at entrance finely papillulate, very fleshy and strongly bent down at base, slightly dorsiventrally flattened, half globular at apex, inside without septum, back-wall callus in form of two insignificant folds united together and forming small pocket below column base. Column stout, shortly cylindric, 1 – 1.2 mm tall, 0.8 – 1 mm wide, wingless, at base finely papillulate; rostellum in form of two prominent, white, forward directed dents. Operculum helmet-shaped, half-globular, 0.7 – 0.8 mm in diameter, with prominent triangular, forward directed beak, obtuse to truncate at apex. Pollinia 4, subsimilar, half-ovoid, arranged in 2 units, bright yellow, held on apex of erect, narrowly oblanceolate stipe 0.5 – 0.6 mm long, placed almost perpendicular to plate-shaped bifid viscidium, ovate in outline 0.3 – 0.4 mm long, 0.15 – 0.2 mm wide. Fruits not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	etymology	Etymology: — The species epithet refers to the names of two sons of Mr. Nguyen Ta Ton, Truong (Nguy ễn Phan Trư ờng) and Quan (Nguy ễn Trung Quân) who found and kindly provided the materials for this study.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	biology_ecology	Ecology and phenology: — Epiphyte on mossy trees. Evergreen broad-leaved montane forests on granite at elevations of about 1700 m a. s. l., very rare. Flowers in July.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E663562FF35FC44DA2909E2.taxon	distribution	Distribution: — Vietnam (Kon Tum Province, Tu Mo Rong and Dak Glei districts), endemic of Ngoc Linh Mountains. Conservation status: — Cleisostoma truongquanii is presently known from a single location in Ngoc Linh Mountains with one documented population, which area has no official protection and experienced currently the wide uncontrolled deforestation. This is inferred as continuing decline in quality of habitat. Accordingly, the one site of occurrence of this species is counted as 1 location. The AOO is estimated to be less than 10 km 2. The species is thus assessed globally as Critically Endangered B 2 ab (iii) following formal criteria proposed by the IUCN (2024). Note: — Cleisostoma truongquanii in its morphology is most close to C. dorsisacculatum Aver. in Averyanov et al. (2016: 330, fig. 6 D-G & 7) sharing rather similar plant habit, shape and color scheme of flowers, and pocket-like back-wall callus. At the same time our new species differs in many characters, such as leaves 4 – 7 cm long (vs. leaves 6 – 14 cm long), inflorescence raceme or panicle with 1 – 4 (5) branches and peduncle 3 – 4 cm long (vs. inflorescence panicle with 4 – 14 branches and peduncle 10 – 18 cm long), pedicel and ovary 1.8 – 3 mm long (vs. pedicel and ovary 4 – 6 mm long), flowers 4 – 5.2 mm across (vs. flowers 6 – 7.5 mm across), sepals 2 – 2.7 mm long (vs. sepals 3.2 – 3.8 mm long), petals 1.7 – 2.1 mm long (vs. petals 3.2 – 3.8 mm long), lip 3.4 – 4.5 mm long from apex of spur to apex of median lobe (vs. lip 4.2 – 5 mm long), side lobes triangular 0.9 – 1.1 mm long and wide, inside flat, without ornamentation (vs. side lobes narrowly triangular, 1.1 – 1.5 mm long, 0.5 – 0.6 mm wide, inside with enrolled fold and prominent papillose callus), median lobe triangular sagittate, 1.9 – 2 mm long and wide; side lobules acute, back directed; median lobule roundish to truncate, disc without ornamentation (vs. median lobe triangular 1.2 – 1.6 mm long, 1.6 – 2.2 mm wide, at apex blunt to roundish or subtruncate, disc with 2 prominent papillose inflations), spur 2 – 2.5 mm long, 1.8 – 2 mm wide, inside at entrance finely papillulate, slightly dorsiventrally flattened, inside without septum (vs. spur 2.8 – 3.4 mm long, 2 – 2.6 wide, inside almost glabrous, dorsally strongly concave, inside with distinct incomplete septum), back-wall callus in form of two insignificant folds united together and forming very small glabrous pocket below column base (vs. back-wall callus in form of large, half-ovoid, finely papillose container 2 – 2.2 mm long, 1.6 – 1.8 mm wide, swelling during anthesis and sometimes opening with age at apex by two narrow lateral splits), column 1 – 1.2 mm tall, 0.8 – 1 mm wide (vs. column 1.6 – 2.2 mm high, 2.4 – 2.6 mm wide), anther 0.7 – 0.8 mm in diameter (vs. anther cap 0.9 – 1 mm in diameter), and pollinarium stipe 0.5 – 0.6 mm long with viscidium 3 – 0.4 mm long (vs. stipe 0.8 – 1 mm long, with viscidium 0.35 – 0.45 mm long). Both species are reported from similar habitats of Central Highlands in southern Vietnam. Meanwhile, flowering of C. truongquanii is observed in July, when C. dorsisacculatum flowers in November.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	diagnosis	Diagnosis: — Micropera vietnamensis morphologically is most close to M. mannii, from which well differs in hairy rachis 8 – 13 cm long bearing to 35 flowers, twice longer pedicel and ovary 7 – 11 mm long, almost purple, distinctly larger flowers 9 – 11 mm across, broadly oblanceolate to oblong narrowly obovate obtuse sepals and petals 5 – 8 mm long, 1.2 – 1.8 mm wide, lip side-lobes obliquely truncate to roundish, and rostellum straight, as long or longer than column.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	materials_examined	Type: — VIETNAM. Dak Lak Province: herbarium specimen prepared from cultivated, wild collected plants, 29 May 2022, L. Averyanov, N. V. Canh, T. Maisak, AL 1339 (holotype LE 01168977 https: // herbariumle. ru /? t = occ & id = 142645, analytical photos LE 01123411 https: // en. herbariumle. ru /? t = occ & id = 137201).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	description	Description: — Herb monopodial perennial epiphytic. Stem rigid, pendulous, simple or few branching near the base, (12) 15 – 30 (35) cm long, covered by leaf sheaths throughout, leafy in apical half, with few light gray roots near base. Leaves sessile with distinct articulation at the base; leaf blade rigid, lorate lanceolate, distinctly conduplicate, keeled below, gradually tapering to shortly bifid apex, (7) 8 – 14 (16) cm long, (0.8) 0.9 – 1.1 (1.2) cm wide. Inflorescences placed opposite leaf base, lax raceme, (10) 12 – 16 (17) cm long; peduncle straight to arching, 2 – 4 cm long, sheathed at base; rachis straight to distinctly zig-zag, with sparse brownish scurfy hairs, (8) 10 – 12 (13) cm long; floral bracts narrowly triangular, acute, 2.5 – 3 mm long. Flowers (9) 9.5 – 10.5 (11) mm across; sepals and petals light pink to purple, often with unclear irregular purple marks; lip pink to purple with white apex. Pedicel and ovary greenish to pink, hairy with brownish scurfy hairs, (7) 8 – 10 (11) mm long, 0.8 – 1 mm in diameter. Sepals and petals broadly oblanceolate to oblong narrowly obovate, obtuse, spreading, (5) 6 – 7 (8) mm long, 1.2 – 1.8 mm wide, lateral sepals shortly connate with lip base, petals little narrower. Lip obscurely 3 - lobe, fleshy, narrowly obovoid, bailer-shaped in outline, (4) 4.5 – 5.5 (6) mm long, narrowing to the base, distally broadening, deeply saccate, at right angle to the ovary; side-lobes obliquely truncate to roundish, erect, with incurved front corner; median lobe minute, broadly triangular. Column foot-less, 1.4 – 1.6 mm tall, twisted, with large, straight, narrowly triangular, oblique rostellum. Operculum hemispheric, 0.6 – 0.7 mm in diameter. Fruits fusiform to elongate cylindrical, stalked, longitudinally ridged capsule (2) 2.4 (2.8) cm long, 2.3. 2 mm in diameter (not ripe).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	biology_ecology	Ecology and phenology: — Epiphyte in lowland evergreen broad-leaved forests. Flowers in May – June.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	distribution	Distribution: — Vietnam (Dak Lak and Quang Binh provinces). Endemic to central Vietnam. Conservation status: — Micropera vietnamensis is presently known from two documented populations located in Dak Lak and Quang Binh provinces distant from each other for about 600 km. The area of both populations has no official protection and experienced currently the wide uncontrolled deforestation. This can be inferred as continuing decline in quality of habitat, number of locations is 2 and AOO is less than 10 km 2. The conservation status of this species is thus estimated as Endangered B 2 a (iii) following formal criteria proposed by the IUCN (2024). Notes: — Plants discovered in Vietnam surely resembles Micropera mannii (Hooker 1890: 36) Tang & F. T. Wang (1951: 94) known from Bhutan and NE India (Assam, Meghalaya, Nagaland, Arunachal Pradesh, Sikkim, West Bengal) why they were erroneously identified as this species two years ago (Averyanov et al. 2022 b). Meanwhile, the study of additional materials reveals a series of characters, which clearly segregate Vietnamese specimens from Indian plants, namely: rachis 8 – 13 cm long, bearing to 35 flowers, hairy with sparse brownish scurfy hairs (vs. rachis glabrous, 2 – 8.5 cm long, bearing less than 18 flowers), pedicel and ovary 7 – 11 mm long (vs. pedicel and ovary 3 – 6 mm long), flowers 9 – 11 mm across, almost purple except white lip apex, lip base uniform bright purple (vs. flowers 6 – 7 mm across, almost white with yellowish lip, lip base with two distinct deep purple stripes), sepals and petals 5 – 8 mm long, 1.2 – 1.8 mm wide, broadly oblanceolate to oblong narrowly obovate, obtuse (vs. sepals and petals 3 – 4.5 mm long, 0.8 – 1.2 mm wide, obovate, roundish to truncate at apex), lip side-lobes obliquely truncate to roundish (vs. lip side lobes obtuse to acute), and rostellum straight, as long or longer than column itself (vs. rostellum sigmoid, down curved shorter than column). Illustrations of plants regarded here as a new species were published earlier (Averyanov et al. 2022 b: 52, fig. 6 A – D). under the name C. mannii. The area of the new species distant from closest locations of C. mannii in NE India for about 1600 km.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6B3563FF35FAB0DD050806.taxon	description	Additional studied specimen (paratype): — VIETNAM, Quang Binh Province: Minh Hoa District, herbarium voucher specimen prepared from cultivated wild collected plant, 11 November 2023, L. Averyanov, Nguyen Van Canh, Truong Ba Vuong, T. Maisak, AL 2582 (LE: LE 01253890 https: // en. herbariumle. ru /? t = occ & id = 213870, analytical photos LE 01124632 https: // en. herbariumle. ru /? t = occ & id = 207912).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	description	(Fig. 13 & 14)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	diagnosis	Diagnosis: — The new species differs from morphologically most similar R. succisa in oblong lanceolate or oblong broadly lanceolate leaves, with almost round apical lobes, light brown tepals and pure white lip, distinct flat callosity on petals, prominent pocket-shaped callus on adaxial side of lip side lobes, two longitudinal ridges inside lip as tall as long, back-wall and front-wall of spur with large callus almost closing spur entrance, and half-ovate rostellum, distinctly longer than tall.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	materials_examined	Type: — VIETNAM. Kon Tum Province: probably Kon Plong District, epiphyte in evergreen forest, at elevation of about 700 m a. s. l., 2 August 2023, Nguyen Van Canh, AL 2235 (holotype LE: LE 01253912 https: // en. herbariumle. ru /? t = occ & id = 213892, photos & drawings LELE 01124287 https: // en. herbariumle. ru /? t = occ & id = 185344, LE 01124838 https: // en. herbariumle. ru /? t = occ & id = 221625, LE 01124839 https: // en. herbariumle. ru /? t = occ & id = 221626).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	description	Description: — Perennial monopodial epiphytic herb. Stem simple or basally branched, rigid, leafy throughout, pendulous, (6) 10 – 16 (18) cm long, (3) 3.5 – 5 (6) mm in diameter (2 – 3 mm when dry), in basal half with few wiry, rigid, flexuose, terete, white, light grey to pale greenish roots, (3.5) 4 – 4.5 (5) mm in diameter (1.5 – 2 mm when dry); internodes (0.8) 1.2 – 1.8 (2.2) cm long. Leaves numerous, sessile, coriaceous, straight to slightly curved, oblong lanceolate to broadly lanceolate, (7) 9 – 12 (14) cm long, (0.8) 1 – 2 (2.2) cm wide, unequally bilobed at apex, with almost round lobes. Inflorescence pendulous raceme or panicle with 2 – 3 branches, (13) 15 – 20 (22) cm long, scape and rachis grassy green, in basal part with dirty purple markings; scape (3.4) 4 – 8 (10) cm long, terete, down curved at base, with (2) 3 – 4 (5) short, broad, dull pale yellowish brownish sterile papyraceus bracts (3) 4 – 6 (7) mm long; inflorescence branches to 10 cm long; rachis straight or slightly curved, longitudinally ridged, greenish with dirty purple markings, to 20 cm long, with many spirally arranged, subdense flowers. Floral bracts pale greenish to dirty purple, narrowly triangular, acuminate, somewhat scarious, (1.2) 1.5 – 2.2 (2.5) mm long, (0.4) 0.5 – 0.6 (0.8) mm wide. Pedicel and ovary (3.5) 4 – 7.5 (8) mm long and (0.6) 0.8 – 1 (1.1) mm in diameter (about 0.5 mm when dry), longitudinally ridged, light greenish, glabrous or with small scattered rusty trichomes, straight or slightly curved, slightly broadening at the base. Flowers widely opening, (6) 6.5 – 7.5 (8) mm across; sepals and petals rather fleshy, light brown, with white base; sepals outside with sparse very small rusty trichomes, lip, column, and anther cap entirely white; pollinia light yellow. Median sepal forward directed, broadly ovate, cucullate, strongly concave, almost hemispheric, round at slightly recurved apex, (3.3) 3.5 – 4 (4.2) mm long and wide (2.5 – 3 mm when dry). Lateral sepals spreading to reflexed, obovate, slightly oblique and concave, rounded at apex, (3.8) 4 (4.2) mm long, (3.3) 3.5 (3.7) mm wide. Petals forward directed, narrowly obovate, truncate, (2.4) 2.6 – 3 (3.2) mm long, (1.6) 1.8 – 2 (2.2) mm broad (about 2.5 × 1.8 mm when dry), slightly oblique, finely irregularly denticulate along margin, in apical half with flat round callosity. Lip spurred, (6.3) 6.5 – 7 (7.2) mm long (from spur apex to the apex of median lobe), 3 - lobed; side lobes almost half-round, parallel and forward directed, (1.4) 1.6 – 1.7 (1.9) mm long, (1.9) 2 – 2.2 (2.3) mm broad at the base, each side lobe inside at front with prominent fleshy pocket-shaped callus; median lobe fleshy, conoid, (1.8) 2 (2.2) mm long, (0.7) 0.8 – 0.9 (1) mm wide, obtuse, forward directed or slightly upright, at middle with prominent, short, erect, longitudinal twin ridge (0.7) 0.8 (0.9) mm tall, median part of the disk with 2 fleshy, short, tall keels, separated by deep longitudinal furrow; spur rectangular obovoid, slightly dorsiventrally compressed, narrowing at the base, saccate, truncate or slightly emarginate at apex, (2.2) 2.5 – 3 (3.2) mm long and wide, inside with incomplete longitudinal septum rising from back-wall and front-wall in the spur middle part. Back-wall callus in form of large, simple. massive callosity almost closing the spur entrance. Column short, broad, slightly back bent, (1.8) 2 (2.2) mm high and wide; at the base from each side with large, fleshy, shortly cylindric or conoid, forwarddirected, finely verruculose auricles; at front with large, forward directed rostellum in form of half-ovate, laterally compressed, twin keel, supporting distally viscidium; stigma concave, obscurely cordate. Operculum placed at front of column, bail-shaped, 2 – 2.2 mm long, 0.8 – 0.9 mm broad, convex, with narrowly triangular beak, tapering to the acute apex. Pollinia 2, ovoid or ellipsoid pollinia, 0.5 – 0.55 mm long, each distinctly notched; stipe (tegula) in form of simple, almost filiform conduplicate stalk, (2.1) 2.2 (2.3) mm long, slightly broadening at arcuate bent apex; caudicles insignificant; viscidium attached to the stipe base, simple, in form of ovate flat, very small plate, about 0.2 mm long. Fruits not seen.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	etymology	Etymology: — The species epithet refers to the name of Mr. Nguyen Truong Binh for his notable role in forest protection and nature conservation in Central Highlands of Vietnam.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	biology_ecology	Ecology and phenology: — Primary and secondary submountain and mountain evergreen broad-leaved forests on granite. Flowers in July – August.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	distribution	Distribution: — Vietnam, Kon Tum Province (probably Kon Plong District). Endemic to central Vietnam. Conservation status: — The species is known up to now only by a single collection from eastern part of Kon Tum Province in southern Vietnam. Any data on the size and geographical extension of the species’ population are not yet available. Hence, the conservation status of the new species is currently identified as Data Deficient (DD). Further field studies are necessary to assess the true conservation status of this rare species. Notes: — New species is most close to R. succisa (Lindley 1826: tab. 1014) Seidenf. & Garay in Seidenfaden (1972: 119) common in Nepal, NE India, Bangladesh, Myanmar, S China (including Hong Kong and Hainan), Thailand, Laos, Cambodia, and Vietnam. From this widespread species our plant differs in leaves oblong lanceolate to broadly lanceolate, 7 – 14 cm long, 0.8 – 2.2 cm wide, with almost round apical lobes (vs. leaves oblong elliptic or oblong narrowly ovate, 5 – 10 cm long, 1.5 – 2.5 cm wide, with triangular truncate apical lobes irregularly denticulate along the margin), light brown tepals and pure white lip (vs. tepals yellow or yellow green, lip white with bright purple stripes at the base of side lobes and yellow spur), distinct flat callosity on petals (vs. petals flat), prominent pocket-shaped callus on adaxial side of lip side lobes (vs. side lobes almost flat), two short and tall, longitudinal ridges inside lip, each as tall as long (vs. lip with low keels, much longer than tall), back-wall and front-wall of spur with large callus almost closing spur entrance (vs. back-wall and front-wall of spur with rather insignificant not closing spur entrance), and half-ovate rostellum, distinctly longer than tall (vs. rostellum half-orbicular, as long as tall or taller). Most probably the new species represents local endemism of mountain area in central part of southern Vietnam known in national geography as Central Highlands.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6A3560FF35FA5CDC73053E.taxon	description	Additional studied specimen (paratype): — VIETNAM. Kon Tum Province: probably Kon Plong District, epiphyte in evergreen forest, at elevation of about 700 m a. s. l., 27 August 2023, Truong Ba Vuong, Nguyen Van Canh, BVL 1893 (VNM VNM 00070010).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6E3564FF35FF33DB680F9F.taxon	description	= Schoenorchis fragrans auct. non Seidenfaden & Smitinand (1963: 611, quoad name): Seidenfaden & Smitinand (1963: 611, fig. 459, quoad plant). (Fig. 15)	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6E3564FF35FF33DB680F9F.taxon	materials_examined	Type: — THAILAND. Chiang Mai Province: Doi Sutep Mt., G. Seidenfaden, T. Smitinand GT 2602 (C fide Pradhan 1978: 912).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6E3564FF35FF33DB680F9F.taxon	biology_ecology	Ecology and phenology: — Miniature branch epiphyte. Lowland and submontane dry evergreen forests. Flowers in July.	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6E3564FF35FF33DB680F9F.taxon	distribution	Distribution: — Vietnam (Gia Lai Province, Dak Doa District). Myanmar, Thailand. Conservation status: — Currently, Schoenorchis seidenfadenii is known in Vietnam from a single location found in an area having no official protection and experienced with wide deforestation and land development. These are indicators of continuing decline in the quality of habitat. The AOO is estimated to be less than 10 km 2. With this information, the species can be assessed as Critically Endangered [CR B 2 ab (iii)]. The species is further distributed in Myanmar and Thailand. Hence, there is a chance of immigration of propagules from adjacent countries. Accordingly, the preliminary assessment of CR is downlisted to Endangered [EN B 2 ab (iii)] for Vietnam. Notes: — The formal record of this species for Vietnam (GBIF & POWO 2024) is based on a wrongly identified specimen (HAL 1084) housed at MO, which in fact is an isotype of S. scolopendria Averyanov (2012: 134). In this connection, the discovery presented here is the first verified record of S. seidendfadenii in Vietnam. It essentially expands the species area to the east. Schoenorchis seidenfadenii in plant habit is superficially very similar to S. fragrans and S. phitamii Averyanov in Averyanov et al. (2017: 25). However, in flower structure, it well differs in twin callus on the lip disc (vs. callus entire). Flowers of S. seidenfadenii are very similar to flowers of S. scolopendria Averyanov (2012: 134), but the first species strikingly differs in a short, erect stem (vs. a long, creeping stem).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
03A0E6426E6E3564FF35FF33DB680F9F.taxon	description	Studied specimen: — VIETNAM, Gia Lai Province, Dak Doa District, plant obtained from local collectors, 16 July 2024, Nguyen Van Canh, AL 3274 (LE: LE 01255163 https: // en. herbariumle. ru /? t = occ & id = 229785).	en	Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Quang, Bui Hong, Nguyen, Khang Sinh, Le, Tuan Anh, Binh, Tran Duc, Maisak, Tatiana V., Nguyen, Cuong Huu (2025): New orchids in the flora of Vietnam X (Orchidaceae, Orchidoideae, tribe Orchideae, Epidendroideae, tribes Gastrodieae, Arethuseae, Cymbidieae, and Vandeae). Phytotaxa 681 (1): 20-54, DOI: 10.11646/phytotaxa.681.1.3, URL: https://doi.org/10.11646/phytotaxa.681.1.3
