Eulophia Brown (1821

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), pp. 20-54 : 31

Eulophia Brown (1821 : tab. 573).

Eulophia bicallosa (D.Don) Hunt & Summerhayes (1966: 60) , Seidenfaden (1983: 38, fig. 22), Seidenfaden, Wood (1992: 541, fig. 245e, f), Comber (1990: 376, 2001: 214), Pearce & Cribb (2002: 252), Chen et al. (2009: 254), Rokaya et al. (2013: 528), Pedersen et al. (2014: 506, fig. 277, plate 43, 2), Jalal & Jayanthi (2015: 22), Lin et al. (2016: 124), Zhou et al. (2016: 58), Aung et al. (2020: 84).

≡ Bletia bicallosa Don (1825: 30) .

( Fig. 5 )

Type: — NEPAL. Buchanan-Hamilton s.n. (holotype BM BM 000525392 photo!).

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.

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.

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, AL2221 ( LE: LE01124265 https://en.herbariumle.ru/?t=occ&id=180620, LE01255216 https://en.herbariumle.ru/?t=occ&id=241570) ; grassland in Dipterocarp forest , April 2023, Nguyen Van Canh, AL2447 ( LE: LE01253859 https://en.herbariumle.ru/?t=occ&id=213839) .

Figures

FIGURE 5. Eulophia bicallosa.A. Flattened flowering plants.B, C. Inflorescences.D–F. Flowers,views fromdifferent sides.G. Flattened sepals, petals, lip (adaxial side), pedicel, ovary and column (side view). H. Lip, front and half-side view. I. Pedicel, ovary and column, side view. J, K. column, front and side view. L. Apical half of column, front view, operculum and pollinarium removed. M. Operculum, view from bottom. N. Pollinarium. Photos by Nguyen Van Canh, from the plant used for preparation of voucher specimen AL2447. Photo correction and design by L. Averyanov and T. Maisak.