sign in sign up
<<
Home , Malaxideae, Oberonia

Phytotaxa 302 (3): 259–265 ISSN 1179-3155 (print edition) http://www.mapress.com/j/pt/ PHYTOTAXA Copyright © 2017 Magnolia Press Article ISSN 1179-3163 (online edition) https://doi.org/10.11646/phytotaxa.302.3.5

Oberonia meegaskumburae (: : ), a new species from Sri Lanka

THARAKA S. PRIYADARSHANA1,3, ISHARA H. WIJEWARDHANE2,3, ANUSHA G. ATTHANAGODA4, NANDUN S. ARANGALA5, ASANKA JAYASOORIYA6 & PANKAJ KUMAR7,* 1College of Forestry, Guangxi University, No. 100 Daxue Road, Nanning, Guangxi 530005, People’s Republic of . 2Sri Lanka School of Agriculture, Department of Agriculture, Karapincha, Kuruwita, Sri Lanka. 3Nature Explorations and Education Team, No: B-1 / G-6, De Soysapura, Moratuwa 10400, Sri Lanka. 493/5, Anuragoda, Papiliyawala, Kirindiwela, Sri Lanka. 5No: 23, Wekanda road, Homagama, Sri Lanka. 6Department of Wildlife Conservation, National Wildlife Research and Training Center (NWRTC), Giritale, Sri Lanka. 7Kadoorie Farm and Botanic Garden, Lam Kam Road, Lam Tsuen, Tai Po, New Territories, Hong Kong. *For correspondence: [email protected]; [email protected]

Abstract

Oberonia meegaskumburae is described and illustrated from Adam’s Peak (Samanala) Nature Reserve, Sri Lanka and dif- ferentiated from its close ally, O. weragamaensis on the basis of larger flowers (3 mm long) in former against smaller (2 mm) in latter; longer floral bracts (1.9 mm) in former against shorter (1 mm) in latter; equal size (> 0.2 mm) of lobules of mid-lobe in former against shorter mid-lobule (< 0.1 mm) in latter; slender, terete and club-shaped tip of lateral lobe curved to face each other in former against sub-triangular, parallel and inflated in latter. Key to all species of Oberonia found in Sri Lanka is provided.

Key words: Adam’s Peak, Samanala Nature Reserve, section Scylla, Oberonia weragamaensis, orchid

INTRODUCTION

The genus Oberonia Lindley (1830:15), named after Oberon, the king of fairies, is one of the tropical orchid genera including around 320 species distributed in South and Southeast to tropical , Madagascar, the Mascarene Islands, New Guinea, Northeast , and the Southwest Pacific islands till Tahiti (Jayaweera 1981, Ansari & Balakrishnan 1990, Pridgeon et al. 2006, Bunpha et al. 2013, Govaerts et al. 2016). Generic name Oberonia Lindl. is conserved over Iridorkis Thouars (1809: 319). The genus comprises of species that are usually epiphyte, sometimes lithophyte and are characterized by their laterally compressed, rarely terete, fleshy and equitant leaves; pendulous or sub-erected inflorescence with densely or laxly arranged minute non-resupinate flowers; labellum sessile, entire or 3–lobed, usually spreading, occasionally with concavity at the base, callus absent; short, lacking foot; pollinia 4, in pairs with unequal size, waxy; viscidium absent; stigma transversely reniform to ovate; rostellum protruding; spur absent. Labellum and habit also play an important role in species identification (Lindley 1830; Ansari & Balakrishnan 1990; Hsu & Chung 2008). During a recent visit in Adam’s Peak (Samanala) Nature Reserve in Kuruwita–Erathna foot path, Ratnapura district, Sabaragamuwa province, Sri Lanka on 31 December 2015, an interesting epiphytic orchid belonging to genus Oberonia was discovered. It was morphologically distinct due to the presence of a 3-lobed midlobe labellum with side lobes elongated and pointing upwards. After a thorough investigation at the National Herbarium, Peradeniya, Sri Lanka (PDA) and perusal of literatures (Jayaweera 1981; Ansari & Balakrishnan 1990; Fernando & Ormerod 2008) we concluded this to be morphologically close to Oberonia weragamaensis Jayaweera (1963:103), however a new species. Hence, we named it Oberonia meegaskumburae. A clear taxonomic account and key to all Sri Lankan Oberonia species are provided.

Accepted by Zhong-Jian Liu: 9 Mar. 2017; published: 4 Apr. 2017 259 TAXONOMIC ENUMERATION

Oberonia meegaskumburae Priyadarshana, Wijewardana & Kumar, sp. nov. TYPE:—SRI LANKA. Ratnapura: Adam’s peak, Seethagagula, 31 December 2015, Wijewardana 012SIT (holotype: NWRTC!). Diagnosis:—Oberonia meegaskumburae is close to O. weragamaensis in having the lateral lobes of the labellum raised above the column and mid-lobe of the labellum divided into three lobules but can be differentiated on the basis of larger flowers (3 mm long in former against 2 mm in latter); longer floral bracts (1.9 mm in former against 1 mm in latter); midlobule of the mid-lobe same size as the side lobules (> 0.2 mm) in the former against a much shorter (< 0.1 mm) mid-lobule in the latter; lateral lobe of the labellum slender and terete with a club shaped tip curved to face each other in former against sub-triangular, parallel and inflated in latter.

Description: herbaceous, epiphyte. Roots vermiform. Stem reduced. Leaves 4 to 5, laterally compressed, fleshy, distichous, oblong-ensiform, sub-acute, 5–6 × 0.5 cm. Inflorescence many-flowered, spike, 10 cm long, pendulous. Peduncle terete. Flowers reddish-brown, opening progressively downwards, 3 × 1.5 mm. Floral bracts slightly longer than the dorsal , ovate, acuminate, acute, 1.9 × 0.6 mm. Sepals and dissimilar, petals longer than sepals. Dorsal ovate, acuminate, acute, 1.6 × 0.4 mm. Lateral sepals orbicular, rounded, 1 × 0.8mm. Petals ciliate, linear- lanceolate, acuminate, acute, 2.1 × 0.15 mm. Lip 1.4 × 0.5 mm. Lateral lobes succulent, terete, incurved towards club shaped apex, apex facing each other, 1.1 mm long. Mid-lobe trifid, lobules equal sized; lateral lobules sub-triangular, diverging, 0.3 × 0.08 mm; mid-lobule, triangular, 0.25 × 0.08 mm. Column short, 0.5 × 0.4 mm. Operculum broad, 0.2 × 0.15 mm. Pollinia 4, hitching in two pyriform pairs, 0.32 × 0.15 mm, clavate. Larger pollinia obovoid, smaller pollinia disc–shaped. Mature fruit reddish–brown, 3.5 × 1.6 mm (ovary with pedicel). [FIGURES 1–2] Flowering:—Flowers throughout December to January. Habitat and Ecology:—Epiphytic plants growing on lichen and moss covered tree trunks; loosely attached on bark, under almost 80% shade. The species was observed only between Seethagagula (6.8223°N, 80.4579°E; 1066 m) and Madahinna Ambalama (6.8195°N, 80.4642°E; 1141 m) at Adam’s peak (Samanala) Nature Reserve, Kuruwita– Erathna footpath, Ratnapura district, Sabaragamuwa province, Sri Lanka. The area belongs to the lowland–wet zone in Sri Lanka (Ashton et al. 1997). [FIGURES 3] Conservation status:—At present, Oberonia meegaskumburae sp. nov. is known only from the Adam’s peak, Kuruwita–Erathna footpath. Unsuccessful efforts were made by the authors to find this new species in the adjacent areas. Hence this species has been assessed as Data Deficient (DD; IUCN 2012) and endemic to Sri Lanka. Etymology:—Species is named after Dr. Madhava Meegaskumbura, a leading taxonomist and herpetologist of Sri Lanka, based at Department of Zoology, University of Peradeniya. Specimens of other allied taxa examined:—SRI LANKA. Oberonia weragamaensis:—Ratnapura District, Weragama, Jayaweera 2037 (PDA! - Holotype); Oberonia tenuis:—Kandy District, Rangala, Corbet’s Gap, December 1960, Jayaweera 2031 (PDA!); Oberonia walliesilvae:—Kandy District, Rangala, March 1960, Jayaweera 2143 (PDA! - Holotype); Oberonia fornicata:—Kandy District, Rangala, Jayaweera 2025 (PDA! - Holotype); Oberonia claviloba:—Kandy District, Ambagamuwa, December 1969, Jayaweera 2144 (PDA! - Holotype); Oberonia dolabrata:—Kandy District, Corbet’s Gap, April 1960, Jayaweera 2160 (PDA! - Holotype). Taxonomic Notes:— Oberonia meegaskumburae shows close affinity with O. weragamaensis and distribution of both species seems to be overlapping and both bear reddish-brown flowers, still these two species are very distinct from each other. O. meegaskumburae has much longer inflorescence (~ 10 cm), comparatively larger flowers (3 cm long) against shorter inflorescence (~ 5.6 cm) and smaller flowers (2 mm long) in O. weragamaensis. Floral bracts are longer (1.9 mm) in O. meegaskumburae with lateral lobes of the labellum erect, converging, terete, raised above the column bearing clavate tips facing each other against shorter floral bracts (1 mm) against subtriangular, erect, fleshy, lying parallel to each other with blunt slightly inflated apex. Triangular mid-lobule of the mid-lobe is same in size with that of subtriangular side lobules in O. meegaskumburae whereas the side lobules of mid-lobe more than three times longer than mid-lobule. Sectional delimitations have been attempted many times for this genus. Lindley (1859) grouped them on the basis of presence (Section: Caulescentes Lindley 1859: 5) and absence of stem (Section: Acaules Lindley 1859: 1). Hooker (1890) grouped them on the basis of very short stem, ensiform radical or subradical leaves (Section Oberonia Hooker 1890: 675), stem short or absent, leaves ensiform, sepal unequal, dorsal lanceolate, lateral very much large, orbicular (Section Scylla Hooker 1890: 684); leaves radical, terete, fleshy (Section: Myosurus Hooker 1890: 685); elongated stem with many equitant short leaves (Section: Acaulescentes Hooker 1890: 685). Schlechter (1911) and Holttum (1953) considered the absence or presence of an articulation at the base of the leaves to be systematically important.

260 • Phytotaxa 302 (3) © 2017 Magnolia Press PRIYADARSHANA ET AL. FIGURE 1. Oberonia meegaskumbura Priyadarshana, Wijewardana & Kumar sp. nov., A. Plant with inflorescence–front view. B. Plant with inflorescence–side view. C. Close-up of inflorescence. D. Close-up of flower. E. Fruit.

Oberonia meegaskumburae (Orchidaceae) Phytotaxa 302 (3) © 2017 Magnolia Press • 261 FIGURE 2. Oberonia meegaskumburae Priyadarshana, Wijewardana & Kumar sp. nov., A. Plant with inflorescence. B. Flower–front view. C. Flower–side view. D–H. Dissected flower; D. Floral bract, E. Dorsal sepal, F1–F2. Petals, G1–G2. Lateral sepals. H. Labellum. I. Pollinium. J. Operculum. K. Fruits. [Drawn by Ishara H. Wijewardhana from live specimens and Wijewardana 012SIT].

262 • Phytotaxa 302 (3) © 2017 Magnolia Press PRIYADARSHANA ET AL. Accordingly Schlechter (1911) recognized two subgenera Apotemnophyllum (leaves with joint) and Menophyllum (leaves without joint). Seidenfaden (1968) grouped the species from mainland Asia into nine sections without giving any names, keeping four sections sunder subgenera Apotemnophyllum. However he considered these groupings artificial. Later unsatisfied by his own sections as well as preceding author’s classification, Seidenfaden (1978) did not assign any section to the species of Oberonia while revising the orchids of Thailand. Ansari & Balakrishnan (1990) grouped Oberonia species from again into six sections without giving any names. Based on the distinct character of the labellum where side lobes are raised vertically above the column, the new species can be placed in the section Scylla of Hooker (1890), section VII of Seidenfaden (1968) and section V of Ansari & Balakrishnan (1990).

FIGURE 3. A view of Adam’s Peak (Samanala) Nature Reserve, Ratnapura district, Sabaragamuwa province, Sri Lanka, habitat of Oberonia meegaskumburae Priyadarshana & Wijewardana & Kumar sp. nov.

TABLE 1. Comparison between Oberonia weragamaensis and O. meegaskumburae sp. nov. Characters Oberonia weragamaensis O. meegaskumburae sp. nov. Leaves 2–8 × 0.3–0.6 cm 5–6 × 0.5 cm Peduncle Pale green in color. Purple in color. Racemes 5.6 cm long 10 cm long Flower 2 mm long, 1.2 mm wide 3 mm long, 1.5 mm wide Floral bracts 1 mm long, 0.52 mm wide 1.9 mm long, 0.6 mm wide Lip 1.2 × 0.8 mm, lateral lobes 0.7 mm long, subtriangular, 1.4 × 0.5 mm, lateral lobes 1.1 mm long, slender, parallel; mid-lobe trifid, lateral lobules subulate, mid- incurve at apex, not parallel; mid-lobe trifid, lateral lobule triangular and much shorter, inconspicuous, < lobules sub-triangular, mid-lobule triangular (> 0.2 0.1 mm long. mm), same size as side lobules. Petals 1.4 mm long, 0.28 mm wide, denticulate or ciliate 2.1 mm long, 0.15 mm wide, ciliate Dorsal sepal 1.2 × 0.52 mm 1.6 × 0.4 mm Lateral sepals 0.6 × 0.74 mm 4–4.2 × 1.2–1.5 mm Column 0.4 mm high, 0.36 mm broad 0.5 mm high, 0.4 mm broad Pollinium 0.3 mm long, 1.2 mm wide 0.32 mm long, 0.15 mm wide Operculum 0.32 × 0.24 mm 0.2 × 0.15 mm Ovary with pedicel 0.8 mm long, 0.3 mm wide 3.5 mm long, 1.6 mm wide

Key to Oberonia species recorded in Sri Lanka (modified from Jayaweera 1981)

1. Lateral lobes of lip at the same level as or below the column; sepals subequal, ovate or oblong-ovate ...... 2 - Lateral lobes of lip rising above the column, erect and parallel or arching; lateral sepals orbicular ...... 9 2. Lip not lobed; pollinia attached to a gland ...... 3 - Lip 3 lobed; pollinia not attached to a gland ...... 5

Oberonia meegaskumburae (Orchidaceae) Phytotaxa 302 (3) © 2017 Magnolia Press • 263 3. Margin of lip entire; bracts broadly subulate ...... O. zeylanica - Main of lip irregularly crenate or dentate; bracts ovate ...... 4 4. Petals linear, 1 mm long; lip fleshy, lateral lobes rounded, mid-lobe trifid, lateral lobules longer than the mid lobule O. forcipata - Petals linear-oblong, 0.86–1 mm long; lip quadrate, concave ...... O. quadrilatera 5. Lip shorter than sepals ...... O. truncata - Lip equal to or longer than sepals ...... 6 6. Bracts longer than the flower ...... O. longibracteata - Bracts longer than the flower ...... 7 7. Petals linear, 1.2 mm long ...... O. wightiana - Petals ovate or ovate-oblong ...... 8 8. Flowers conspicuously whorled; bracts ovate-lanceolate, pilose, margin irregular; lip obcuneately obcordate, lateral lobes reduced to rounded knobs, mid-lobe bifid, margins distantly crenate ...... O. thwaitesii - Flowers not conspicuously whorled; bracts lanceolate, acuminate; lip twice as long as sepals; conspicuously and irregularly crenate, lateral lobes orbicular, mid-lobe 2-lobulate ...... O. recurva 9. Petals ciliate, lip 3-lobed ...... 10 - Petals not ciliate ...... O. tenuis 10. Petals oblong-lanceolate; plant small ...... O. dolabrata - Petals lanceolate or linear-lanceolate ...... 11 11. Mid-lobe of lip ciliate entirely along the margin or at the tips of the lobules only ...... 12 - Mid-lobe of lip not ciliate ...... 13 12. Lateral lobes of lip subulate, erect, parallel, mid-lobe semilunate; dorsal sepal lanceolate, straight and parallel to the petals, apex ciliate ...... O. scyllae - Lateral lobes of lip clavate, arched and, overlapping behind the column, Mid-lobe trifid, ciliate at the tips, lateral lobules subulate, diverging; lateral sepals orbicular, rounded, petals lanceolate, shaggy ...... O. claviloba 13. Dorsal sepals and petals ciliate ...... O. fornicata - Dorsal sepals not ciliate, only petals ciliate ...... 14 14. Petals lanceolate; lateral sepals broadly orbicular-ovate, obtuse; lateral lobes of lip arched, mid-lobe bifid, concave, lobules bluntly subulate and diverging ...... O. walliesilvae - linear lanceolate, dorsal sepals oblong or ovate, acuminate; mid-lobe trifid ...... 15 15. Lateral lobes of lip parallel, semi-lanceolate; mid-lobule short (< 0.1 mm), triangular and blunt at apex, petals dentate ...... O. weragamaensis - Lateral lobes of the lip not parallel, diverging then converging towards the apex, terete; mid-lobule long (> 0.2 mm), triangular and sharp at apex, petals ciliate ...... O. meegaskumburae

ACKNOWLEDGEMENTS

We wish to thank National Wildlife Research and Training Center (NWRTC), Sri Lanka for issuing the necessary permit and support. Champika Bandara, National Herbarium, Peradeniya, Sri Lanka (PDA) for help with specimens. Yu-Ling Li for fruitful discussions and suggestions on genus Oberonia; Leena Priya Segaran (National University of Singapore), Sameera Suranjan Karunarathna (Nature Explorations and Education Team), Buwaneka Pathirana and Nimantha Aberathna for their support and encouragement.

REFERENCES

Ansari, R. & Balakrishnan, N.P. (1990) A Revision of the Indian species of Oberonia. Orchid Monographs 4: 1–82. Ashton, M., Gunathilake, C.V.S., De Zoysa, N., Dassanayake, M.D., Gunatilake, N. & Wijesundara, S. (1997) A field guide to the common trees and shrubs of Sri Lanka. Wildlife Heritage Trust of Sri Lanka, Colombo, 432 pp. Bunpha, K.O., Pedersen, H.Æ. & Sridith, K. (2013) Establishing species distributions in large tropical plant genera: insights from twelve new Thai records of Oberonia (Orchidaceae). Blumea 58 (1): 71–76. https://doi.org/10.3767/000651913X672299 Chen, S.C., Ormerod, P. & Wood, J.J. (2009) Oberonia Lindl. In: Wu, Z.Y., Raven, P.H. & Hong, D.Y. (Eds.) Flora of China 25. Science Press, Beijing, Missouri Botanical Garden, St. Louis, pp. 236–245. Fernando, S.S. & Ormerod, P. (2008) An annotated checklist of the orchids of Sri Lanka. Rheedea 18: 1–28. Govaerts, R., Campacci, M.A., Baptista, D.H., Cribb, P.J., George, A., Kreutz, K. & Wood, J.J. (2016) World checklist of Orchidaceae. The Board of Trustees of the Royal Botanic Gardens, Kew. Available from: http://www.kew.org/wcsp/monocots/ (accessed 8 August 2016) Holttum, R.E. (1953) A revised flora of Malaya 1, orchids of Malaya (2nd edition). Government Print Office, Singapore, 753 pp.

264 • Phytotaxa 302 (3) © 2017 Magnolia Press PRIYADARSHANA ET AL. Hooker, W.J. & Hooker, J.D. (1888) Icones Plantarum [Hooker’s] Icones plantarum], volume. 18. t. 1782. Hooker, J.D. (1890) Orchidaceae. In: Hooker, J.D. (Ed.) Flora of British India, vol. 6. Reeve, London, pp. 1–198. Hooker, J.D. (1882) Flora of British India, Vol. 3. L. Reeve & Co., London, 712 pp. Hsu, T.C. & Chung, S.W. (2008) Oberonia segawae (Orchidaceae): A new orchid species in Taiwan. Taiwania 53 (2): 165–169. Jayaweera, D.M.A. (1963) New Orchids from Ceylon. Harvard University. Botanical Museum leaflets 20 (4): 93–116. Jayaweera, D.M.A. (1981) Orchidaceae. In: Dissanayake, M.D. (Ed.) A Revised Handbook to the Flora of Ceylon, 2. Oxford and IBH, New Delhi, pp. 9–38. Lindley, J. (1839) Miscellaneous notices. Edwards’s Botanical Register 25 (misc.): 1–95. Available from: http://www.botanicus.org/ item/31753002748389 (accessed 5 July 2016) Lindley, J. (1859) Folia orchidacea, ed. Matthews, London, 414 pp. http://dx.doi.org/10.5962/bhl.title.51709 Lindley, J. (1840) The genera and species of orchidaceous plants. Ridgways, London, 554 pp. Ministry of Environment (2012) The National Red List 2012 of Sri Lanka; Conservation Status of the Fauna and Flora. In: Weerakoon, D.K. & Wijesundara, S. (Eds.) Present Status of family Orchidaceous in Sri Lanka. Colombo, Sri Lanka, pp. 293–301. Pridgeon, A.M., Cribb, P.J., Chase, M.C. & Rasmussen, F.N. (2006) Epidendroideae (Part One). Genera Orchidacearum 4. Oxford University Press, New York, Oxford, 672 pp. Seidenfaden, G. (1968) The genus Oberonia in mainland Asia. Dansk Botanisk Arkiv 25 (3): 1–125. Seidenfaden, G. (1978) Orchid genera in Thailand VII. Oberonia Lindl. and Sol. ex Sw. Dansk Botanisk Arkiv 34 (1): 1–94. Schlecter, R. (1911) Die Orchidaceen von Deutsch New-Guinea. Repertorium Specierum Novarum Regni Vegetabilis, Beihefte 1: 1– 1079. Thouars, A.D.P. (1809) Mémoires lus à la primière class de I’Institut, sue I’histoire des plantes Orchidees des iles australes d’ Afrique. Bulletin des sciences / par la Société Philomathique de Paris 19: 314–319.

Oberonia meegaskumburae (Orchidaceae) Phytotaxa 302 (3) © 2017 Magnolia Press • 265