全 文 ：植 物 分 类 学 报 45 (3): 321–323(2007) doi:10.1360/aps050143
Acta Phytotaxonomica Sinica http://www.plantsystematics.com
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Received: 29 September 2005 Accepted: 9 January 2007
* Author for correspondence. Present address: Department of Botany, University of Kalyani, Kalyani-741 235, Nadia, West Bengal,
India. E-mail: ; .

Myrmechis bakhimensis D. Maity, N. Pradhan & G. G. Maiti,
a new species of Orchidaceae from Sikkim Himalaya
1Debabrata MAITY* 1Neelima PRADHAN 2Gaurgopal MAITI
1(Botanical Survey of India, Sikkim Himalayan Circle, Gangtok-737 103, Sikkim, India)
2(Department of Botany, University of Kalyani, Kalyani-741 235, Nadia, West Bengal, India)
Abstract Myrmechis bakhimensis D. Maity, N. Pradhan & G. G. Maiti (Orchidaceae), a new
species from Sikkim Himalaya, is described and illustrated. The new species most closely
resembles M. japonica (Reichb.) Rolfe and M. chinensis Rolfe with similar shape and size of
lamina and the “T”-shaped epichile, but differs by the perfectly glabrous and eciliate floral
bract, 5-nerved dorsal sepal, and emarginate, mucronate epichile.
Key words Myrmechis, Myrmechis bakhimensis D. Maity, N. Pradhan & G. G. Maiti,
Orchidaceae, new species, Sikkim Himalaya.
A specimen of Myrmechis Bl. was collected by the senior author from the evergreen
temperate forest at an altitude of 3400 m belonging to the jurisdiction of Kanchenjunga
Biosphere Reserve, Sikkim in July 25th, 1999. Basically due to the presence of “T”-shaped
epichile having emarginate and mucronate apex, this collection is not matched with that of the
commonly known species M. pumila (Hook. f.) Tang & Wang found both in the Sikkim and
Bhutan Himalayas (Pearce & Cribb, 2002; Chen et al., 2006). Further, based on studies of the
genus Myrmechis for its described six species from South-east Asia, especially China, Japan
and Thailand (Mabberley, 1997), this specimen was considered to be a new one. This
collection is strikingly different from that of Myrmechis pumila by having “T”-shaped lip
instead of “Y”-shaped nature. However, further observed characterisation of the reproductive
parts reveals its affinities with M. japonica and M. chinensis where the “T”-shaped lip has
subquadrate basal calli.
This new taxon is described and illustrated along with a comparison for few important
characters with its two related species.
Myrmechis bakhimensis D. Maity, N. Pradhan & G. G. Maiti, sp. nov. Fig. 1
Differt a M. japonica (Reichb.) Rolfe bracteis floralibus perfecte glabris, eciliatis; sepalo
dorsali 5-nervi; petalis obliquis; epichilio mucronato, emarginato; ovarioque glabro.
Type: India. West Sikkim, Bakhim to Dzongri, alt. 3400 m, terrestrial, along track sides,
in moist, shady, humid situation, in evergreen temperate forest, 1999-07-25, D. Maity 21921
(holotype, CAL; isotypes, BSHC, PE).
Terrestrial herb, to 12 cm tall; stem elongate, creeping at base and rhizomatous, erect
above, ca. 2 mm in diam., glabrous; leaves few; lamina orbicular-ovate, 5–9×5–8 mm,
margin entire, apex rounded, glabrous, nerves prominent, abruptly narrowed into a petiole;
petioles to 5 mm long, sheathing at base, scarious; stem often interrupted by scale leaves;
peduncle ca. 10 mm long, with few scattered hairs; flower solitary or two, terminal, white,
resupinate; floral bracts oblanceolate-oblong, 4–4.5×2 mm, acute, 1-nerved, shorter than
Acta Phytotaxonomica Sinica Vol. 45 322


Fig. 1. Myrmechis bakhimensis D. Maity, N. Pradhan & G. G. Maiti. A, habit; B, leaf (magnified); C, floral bract; D,
floral parts; E, column with ovary. Drawn by D. Maity from the holotype, D. Maity 21921, CAL.
No. 3 MAITY et al.: Myrmechis bakhimensis, a new species of Orchidaceae from Sikkim Himalaya 323
ovary, perfectly glabrous, eciliate; sepals connate at base to 1 mm; dorsal sepal ovate, 5–5.5×
3 mm, concave, apex obtuse, 5-nerved; lateral sepals obliquely ovate, 6–6.5×3 mm, apex
obtuse, 1-nerved; petals oblong-elliptic with abruptly narrowed apex, oblique, ca. 6×3 mm,
entire, apex obtuse, recurved, 1-nerved; lip 3-partite, ca. 6×3 mm; hypochile widely saccate
at base, with two quadrate calli adaxially; mesochile ca. 2.5 mm long, narrowly clawed,
convolute, smooth, glabrous; epichile divided into 2 quadrate lobes, “T”-shaped with the
mesochile, ca. 3×1.5 mm, apex slightly lobed with a distinct mucro; mucro 0.5–0.7 mm long;
column cylindric, ca. 1 mm long; ovary terete, twisted, ca. 6.5×2 mm, glabrous. Fl. Jul.
This new taxon, Myrmechis bakhimensis, is closely related to M. japonica (Reichb.)
Rolfe and M. chinensis Rolfe in respect of shape and size of lamina and the “T”-shaped
epichile, but differs in features of floral bract, nervation of dorsal sepal and apex of epichile.
In M. bakhimensis the floral bract is perfectly glabrous with eciliate margin while in M.
japonica and M. chinensis it is sparsely villous and ciliate. The dorsal sepal is 5-nerved in the
new species but 1-nerved in other cases. Moreover, the shape of petal is oblong-elliptic in the
new taxon but ovate and ovate-oblong in M. chinensis and M. japonica, respectively. The new
species is also distinct by having smooth, glabrous mesochile and much wider epichile (ca. 3
mm wide) with its emarginate, mucronate apex.
The size of epichile (3–3.5 mm wide) is alike in M. japonica and the new taxon but
narrower (1–1.5 mm wide) in M. chinensis. The emarginated and mucronate nature of epichile
signifies the independent status of the new taxon from its closely allied species.
This new taxon possesses some similar features with that of M. glabra Bl. by having
glabrous bract and truncate epichile, while it is distinctly different by the presence of
orbicular-ovate lamina with rounded apex and the scattered hairy scape. M. glabra is with
ovate-cordate lamina having acute apex and glabrous scape and bract.
This species is known only from its type locality, Bakhim, West Sikkim. The specific
epithet refers to the type locality of the species.
Acknowledgements We thank the Joint Director, Botanical Survey of India, Sikkim
Himalayan Circle, Gangtok, Sikkim for providing facilities and encouragement and to the
Joint Director, Botanical Survey of India, Central National Herbarium (CAL), Howrah for
giving permission to consult the herbarium and library.
References
Chen X-Q, Zhu G-H, Ji Z-H, Lang K-Y, Luo Y-B, Cribb P C. 2006. Orchidaceae. In: Wu Z-Y, Raven P H eds.
Flora of China. Beijing: Science Press; St. Louis: Missouri Botanical Garden Press.
Mabberley D J. 1997. The Plant Book: A Portable Dictionary of Vascular Plants. 2nd ed. Cambridge:
Cambridge University Press.
Pearce N R, Cribb P C. 2002. Flora of Bhutan 3 (3. The Orchids of Bhutan). Royal Botanic Garden,
Edinburgh. 99–101.