Odontochilus umbrosus (Aver.) Ormerod (2002: 225)

Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Nguyen, Khang Sinh, Nuraliev, Maxim S., Nguyen, Cuong Huu, Ormerod, Paul A., Maisak, Tatiana V., Diep, Dinh Quang, Lyskov, Dmitry F. & Nong, Duy Van, 2023, New orchids in the flora of Vietnam VII (Orchidaceae: tribes Cypripedieae, Cranichideae, Orchideae, and Collabieae), Phytotaxa 619 (4), pp. 255-276 : 264

Odontochilus umbrosus (Aver.) Ormerod (2002: 225) , Averyanov (2008: 143), Averyanov et al. (2019a: 36).

≡ Pristiglottis umbrosa Averyanov (1996: 75) . Type: — VIETNAM. Kon Tum Province: Dak Gley District, 15–18 km to NW of Dak Gley Town, between Mang Khen (Dak Che) and Dak Polo villages, near Laos boundary, primary evergreen mountain forest at 1250–1450 m, 22 November 1995, L. Averyanov , N. T . Hiep , P. K . Loc VH 1932 (holotype LE01058603 https://en.herbariumle.ru/?t=occ&id=8798, isotypes HN, MO-3248350/ A:5172257) .

= Odontochilus putaoensis X.H.Jin, L.A.Ye & A.T.Mu in Aung et al. (2018: 20), Lanorsavanh et al. (2019: 87), Ormerod et al. (2021: 178), Sun et al. (2021: 201), syn. nov. Type: — MYANMAR. Kachin State: Putao township, Hponkanrazi Wildlife Sanctuary, subtropical evergreen broad-leaved montane forest, 2000 m, 20 October 2014, X.H.Jin et al. PT-ET 959 (holotype PE).

Ecology and phenology in Vietnam:—Primary evergreen broad-leaved humid submontane and montane forests on granite at elevation of 1000–1500 m a.s.l., usually along shady stream canyons. Flowers in October–January.

Distribution:— Vietnam (provinces Dak Nong: Dak Glong District; and Kon Tum: Dak Gley District). China (Southeast Yunnan), Laos (Bolikhamsai, Luang Namtha and Champasak provinces), Myanmar (Kachin State).

Conservation status:—Given the wide distribution of this species outlined here, its global conservation status is here estimated as Least Concern (LC) according to the criteria proposed by the IUCN Standards and Petitions Committee (2023).

Notes:—The analysis of available herbarium materials and published detailed illustrations provides a clear evidence on almost full identity of Odontochilus putaoensis described from Myanmar ( Aung et al. 2018) and additionally reported from Laos and South China ( Lanorsavanh et al. 2019, Sun et al. 2021) with O. umbrosus . In particular, it is evident that Aung et al. (2018) overlooked the existence of O. umbrosus , since they have not included it into their key to the species of Odontochilus in mainland Southeast Asia. Accordingly, here we reduce O. putaoensis to a synonym of O. umbrosus . The degree of mesochile lobe dissection into fringes looks variable and not too stable in the available material. Hence, we consider forms with toothed and long-fringed mesochile lobes as marginal forms of a single species.

Studied specimens:— LAOS. Champasak Province: 15º04ʹ21.1ʹʹN 106º12ʹ19.2ʹʹ, elevation of 1150 m, 28 November 2019, N. L. Orlov, L. K. Iogansen AL 1255 ( LE01067232 https://en.herbariumle.ru/?t=occ&id=12871) ; Luang Namtha Province: Luang Namtha District, Nam Kong Village, Nam Ha National Protected Area , around point 21º11´543N, 101º22´874E, at elevation of about 1100 m, 26 September–2 October 2017, N. L. Orlov, L. K. Ioganssen NLO 083 (photos LE01061433 https://en.herbariumle.ru/?t=occ&id=8757) . VIETNAM. Dak Nong Province : Dak Glong District, Dak Plao Municipality, steep mountain slopes of Ta Dung Mountains at elevation of about 1250 m around point 11º52’30’’N 108º01’12’’E, primary broad-leaved evergreen closed wet forest on SW slopes composed with crystalline highly metamorphosed sandstone, terrestrial and lithophytic creeping herb along shady rocky stream valley, leaves uniform dark green, sepals pinkish-brown, sepals and lip white, rare, 1 December 2005, flowered under cultivation in Hanoi, 9 November 2005, L. Averyanov et al. HLF 5611a ( HN, LE01058601 https://en.herbariumle. ru/?t=occ&id=8796) ; Dak Nong Province: Ta Dung Mountains, 2011, Truong s.n. (photos LE01090286 https:// en.herbariumle.ru/?t=occ&id=79743) .