Oberonia pachyrhachis (Orchidaceae): a newaddition to the flora of Manipur, India

Th. Surbala Devi, P.D. Singh, B.G. Somkuwar, S.S. Thorat & S. Kumar*

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Institute of Bioresources and Sustainable Development, Imphal-795001, Manipur, India* author for correspondance sanjeet.biotech@gmail.com________________________________

AbstractOberonia pachyrhachis Reichenbach f. ex J.D. Hooker, a little known orchidspecies, has been collected from Senapati district, Manipur, belonging tothe Indo-Burma biodiversity hotspot region, India. The species is describedand illustrated. For easier identification, information on its host plants andthe ecology of the collection sites is provided.

RésuméOberonia pachyrhachis Reichenbach f. ex J.D. Hooker, une espèce d'orchidéespeu connue, a été collecté dans le district de Senapati, Manipur (Inde), quifait partie de la région à très forte biodiversité Indo-birmane. L'espèce estbrièvement décrite et ilustrée. L'écologie des sites de collecte et les planteshôtes des spécimens collectés sont précisées, pour rendre plus aiséel'identification de l'espèce sur le terrain.

Keywords: ex situ conservation, host plant, Indo-Burma biodiversityhotspot, Senapati, vegetative propagation.Mots clés : conservation ex situ, multiplication végétative, plantes hôtes,région à forte biodiversité Indo-birmane, Senapati.

Manuscrit reçu le 18/01/2018 Article mis en ligne le 22/02/2018 – pp. 1-7

IntroductionThe orchid flora of Manipur, India, is quite rich yet poorly known and needextensive exploration for studying the diversity and status of orchidspecies in the region (Misra, 2007; Linthoingambi et al., 2015; Kumar et al.,2016). The most commonly reported species belong to the generaBulbophyllum, Dendrobium, Coelogyne, Cymbidium, Eria, Liparis, Vanda etc;the least common once are representatives of Acampe, Agrostophyllum,Cephalantheropsis, Dienia, Dickasonia, Epigeneium, Flickingera, Goodyera,Habenaria, Ione, Neogyna, Oberonia, Otochilus, Panisea, Pecteilis, Phaius,Pholidota, Pleione, Sunipia, Thunia, Zeuxine, Tropidia etc. Among the leastreported species from the aforesaid region, Oberonia Lindley (Orchidaceae,Epidendroideae, Malaxideae, Malaxidinae) shows surprising diversity andis less explored. The genus was described by John Lindley in 1830 (Chowluet al., 2012; Chowlu et al., 2014). It is characterized by fleshy, flat, ensiformleaves, sub-erect or drooping inflorescence with many densely arrangedflowers. The flowers have usually sub similar sepals and petals, a shortcolumn and 4 pollinia. The genus is comprised of 329 species distributed intropical South, South-east Asia, tropical Africa, Madagascar, Philippines,New Guinea, Australia, Pacific Islands etc (Pearce & Cribb, 2002; Geiger &Kocyan, 2017; Chowlu & Rab, 2017). In India, about 68 Oberonia specieshave been reported (Ansari & Balakrishnan, 1990; Misra, 2007; Narayananet al., 2010), out of which about 40 species are found in the Indo-Burmabiodiversity hotspot & Himalayan regions. Among them, about 12 arefound in Manipur. During the survey of orchid species of Manipur, inJanuary 2018, under the project “Orchid Bioresources of the North-EastIndia Conservation database development and information networks”funded by the Department of Biotechnology, Government of India (grantno. 102/I.F.D./SAN/4311-4316; Serial No. 435-443-reg./grant), the authorsfound a large population of an epiphytic Oberonia near Mao in the Senapatidistrict of Manipur, which lies on the Indo-Burma biodiversity hotspot.After critical study these plants were identified as a taxon not yet recordedfor the region. A brief description and photographs of the species, andnames of the host plants are provided to ease identification in the field.

Material and methodsTwenty plants (one of them being illustrated on Fig. 1) were collectedfrom the Mao region (25° 30' 01.4ʺ N & 94° 07ʹ 53ʺ E; 1695 m) and put

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into cultivation in the NationalBioresources Park, Haraorou,Imphal East, Manipur, so as tocarry ex situ conservation out.Vegetative propagation (Fig. 2b)is in progress in order to preparea future reintroduction in thewild in the Indo-Burma biodiver-sity hotspot regions. All parts ofthe plants were photographedand the images were analysedusing Adobe Photoshop. Herba-rium material (ORC-BDBD-IBSD/2017-0004 – Fig. 2a) wasprepared as usually and depositedin the Bioresources Database andBioinformatics Division of the

Fig 1. Oberonia pachyrhachis in situat Mao, Senapati district, Manipur

Institute of Bioresources and Sustainable Development (IBSD), Imphal,India. The plant identification was based on the critical study of theirmorphology and key characters and the consultation of the flowerimages from different social network groups (The Flora: an initiativeof Ambika Prasad Research Foundation, Indian Flora).

Fig 2. Oberonia pachyrhachis, collected plantsa: collection, b: vegetative propagation

Oberonia pachyrachis in Manipur – Surbala Devi et al.

ResultsThe taxon has been identified as Oberonia pachyrhachis.

Oberonia pachyrachis H.G. Reichenbach ex JD HookerFlora of British India 5:681 (1885)Synonyms: Iridorchis pachyrhachis (H.G. Reichenbach ex JD Hooker) Kuntze(1891); Oberonia umbraticola Rolfe (1909).

Description: small epiphytic orchid up to about 15 cm tall; root fibrous, upto 2.0 cm long; leaves 3-5, narrowly ensiform, acuminate, slightly falcate, ofunequal size, 4-15 × 0.4-0.9 cm; inflorescence straight and fleshy, adnate tothe leaf apex, densely many-flowered, compressed, tapering; floral bractsovate, deeply serrate; flower minute, in pits, pale brown, 0.9-1.2 mm, sessil;sepals ovate or elliptic, 0.9 × 0.6 mm; petals oblong, apex obtuse, 0.6 × 0.3mm; lip ovate, concave, longer than the sepals, entire; pedicel very short;column short; capsule small, about 0.3-0.4 cm, subovoid-ellipsoid (Fig. 3).

Distribution: India (Uttarakhand, Sikkim, Arunachal Pradesh, WesternHimalayas, Eastern Himalayas, Assam, Manipur, Senapati district),Myanmar, Nepal, Bhutan, Thailand, Vietnam, Chinese Himalayas, YunnanChina, Nepal, Myanmar, Thailand and Vietnam (Jalal et al., 2008; Yonzoneet al., 2012; Gogoi et al., 2015; Jalal & Jayanthi, 2015).Rao (2010) reported this species from the Western and Eastern ArunachalPradesh and Yonzone et al. (2012) from the Himalayan region of India.Hence the present collection is a new record to the flora of Manipur andextends the distribution of the species up to the Indo-Myanmar border inthe northeastern India. The reports of Oberonia species reflect its presencein two important biodiversity hotspots, Indo-Burma and Eastern Himalayain the northeastern region of India.

Flowering time: October-January; Fruiting time: February-June.

Habitat: evergreen forest and cold regions.

Conservation status: it was observed that, in similar altitude of adjoiningareas, there were no Oberonia species due to lack of host trees (Table 1) or todeforestation.

AcknowledgementsAuthors are thankful to the Director, Institute of Bioresources andSustainable Development, Manipur and local communities of Indo-Burmaregions, India.

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Fig 3. Oberonia pachyrhachisa & b: leaves arrangements, c & d: inflorescences, e: dry flowers and fruits,

f: habit, g & h: root systems

Oberonia pachyrachis in Manipur – Surbala Devi et al.

Scientific names Family Local namesCarpinus viminea Betulaceae UyungTerminalia myriocarpa Combrataceae TolhaoLagerstroemia speciosa Lytharaceae JarulGmelina arborea Lamiaceae WangCryptocarya amygdalina Lauraceae Tundur

Table 1: host plants of Oberonia pachyrachis in the study area

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Oberonia pachyrachis in Manipur – Surbala Devi et al.