Occurrence and Red List Assessment of Hemipilia purpureopunctata () in India

D.K. Agrawala1*, Samiran Panday1, Manas Bhaumik2 & Avishek Bhattacharjee3

______1 Botanical Survey of India, Sikkim Himalayan Regional Centre, Gangtok, India - 737103. 2 Botanical Survey of India, Industrial Section, Indian Museum, Kolkata, India - 700016. 3 Central National Herbarium, Botanical Survey of India, Howrah, India - 711103 *Corresponding author: [email protected] ______

Abstract Hemipilia purpureopunctata (Kai-Yung Lang) Xiao-Hua Jin, A. Schuiteman & Wei-Tao Jin, a curious terrestrial orchid, has been located from Arunachal Pradesh, India. Although it has been indicated as occurring in Arunachal Pradesh in earlier literature, the present collection is the first authentic specimen of this species collected from India. A brief description, photographs, phenology and distribution of this species are provided for easy recognition in the field. Its threat status assessment has also been done in Indian perspective by applying the IUCN criteria.

Résumé Hemipilia purpureopunctata (Kai-Yung Lang) Xiao-Hua Jin, A. Schuiteman & Wei-Tao Jin, une curieuse orchidée terrestre, a été observée en Arunachal Pradesh, Inde. Bien que l'espèce ait été mentionnée dans la littérature antérieure comme présente dans cet état, la présente collection en constitue le premier spécimen réel collecté en Inde. Pour faciliter son identification sur le terrain, nous proposons ici une brève description de l'espèce, des photographies et des notes sur sa phénologie et sa répartition

Manuscrit reçu le 21/08/2019 Article mis en ligne le 22/01/2020 – pp. 1-8 géographique. Enfin son statut de danger a été évalué pour l'Inde sur la base des critères IUCN.

Keywords: Arunachal Pradesh, Hemipilia, India, IUCN Criteria, occurrence, threat status. Mots-clés : Arunachal Pradesh, critères IUCN, Hemipilia, Inde, occurrence, statut de danger.

Introduction During the study of Indian Orchidaceae for ‘Flora of India’, the authors came across an interesting terrestrial orchid specimen in ARUN’s collection, collected by one of us (MB) in 2012 from Monigang, West Siang district of Arunachal Pradesh, India. Morphology of this specimen was compared with available descriptions in literature on Indian Orchids [Hooker (1890), King & Pantling (1898), Pradhan (1976), Chowdhery (1998), Pearce & Cribb (2002), Lucksom (2007), Rao (2010), Lawkush (2015)] and herbarium specimens available at ARUN, CAL, ASSAM, APFH, OHT and BSHC. Finally the specimen was not matching with the identity of any species available in these literature and herbaria. Presence of underground, fleshy, ellipsoid tubers with floral morphology, especially the spurred, 3- lobed labellum and erect columnar structure with 2 lateral appendages, the erect, sessile anther with two parallel locules, the shallowly 3-lobed rostellum, the 2-lobed stigma and the two erect sectile pollinia attached by a slender caudicle to a small naked viscidium, place it in the sub-family with related genera like, Habenaria Willdenow (1805: 5), Hemipilia Lindley (1835: 296), Brachycorythis Lindley (1838: 363), Reichenbach (1852: 227) etc., but the purple spots in the entire vegetative and perianth parts, together with a wide apically globular-swelled spur and the small rostellum, make it unique among all the species known so far from India. Further study of literature pertaining to neighboring countries, including that of China [Lang & Tsi (1978), Luo & S.C. Chen (2003), S.C. Chen et al. (2009), Jin et al. (2014)] led us to identify it as Hemipilia purpureopunctata (Kai-Yung Lang) Xiao-Hua Jin, Schuiteman & Wei-Tao Jin in Wei-Tao Jin, Xiao-Hua Jin, A. Schuiteman, De-Zhu Li, Xiao-Cruo Xiang, Wei-Chang Huang, Jian-Wu Li & Lu-Qi Huang (2014: 50). Hemipilia purpureopunctata was originally described [as Habenaria purpureopunctata Kai-Yung Lang in Lang Kai-Yung & Tsi Zhan-Huo (1978:

2 127)] from a specimen from Bomi, Tibet (Southeastern Xizang, China). The generic placement was based on the presence of small rostellum, naked viscidia and two protruding, clavate stigmas. Later, Lang (1980) mentioned that Habenaria purpureopunctata is intermediate between Habenaria and Hemipilia. Subsequently, Luo & S.C. Chen (2003) established a new monotypic genus Hemipiliopsis Yibo Luo & S.C. Chen (2003: 450) [Type: Hemipiliopsis purpureopunctata (Kai-Yung Lang) Yibo Luo & S.C. Chen (2003: 450)] based on the Hemipilia-like morphology in having purple- spotted stem, leaf and other parts, as well as a large mouthed spur with a globular-swelled tip. They also placed the new genus in the sub-tribe Orchidiinae (sensu Dressler, 1993) instead of Habenariinae with support from nuclear ribosomal DNA internal transcribed spacers (ITS) data. Later, Jin et al. (2014) have reassessed the generic delimitation of Orchidiinae and some Asiatic Habenariinae based on three DNA markers (plastid matK, rbcl, and nuclear ITS) coupled with morphological characters and combined Hemipiliopsis with Hemipilia. Hemipilia purpureopunctata has been mentioned as distributed in Assam by Luo & S.C. Chen (2003) and S.C. Chen et al. (2009) without referring to any voucher specimen or literature. Similarly, Govaerts et al. (2019) and Singh et al. (2019) have included this species from Arunachal Pradesh, India without any information on its habitat details or voucher specimen. Thus, the present specimen from Arunachal Pradesh confirms its occurrence in India and also forms the first authentic voucher specimen of this species collected from India. A brief description, photographs, phenology and distribution of this species are provided for easy recognition in the field. Its threat status has been assessed in Indian perspective by applying the IUCN criteria.

Taxonomic treatment Hemipilia purpureopunctata (Kai-Yung Lang) Xiao-Hua Jin, Schuiteman & Wei-Tao Jin in Wei-Tao Jin, Xiao-Hua Jin, A. Schuiteman, De-Zhu Li, Xiao-Cruo Xiang, Wei-Chang Huang, Jian-Wu Li & Lu-Qi Huang Molecular Phylonegetics and Evolution 77: 50, fig. 3(e), 2014. Habenaria purpureopunctata Kai-Yung Lang, in Lang Kai-Yung & Tsi Zhan-Huo, Acta Phytotaxonomica Sinica 16(4): 127, fig. 2, 1978. Hemipiliopsis purpureopunctata (Kai-Yung Lang) Yibo Luo & S.C. Chen, Novon 13: 450, 2003; S.C. Chen et al., Flora of China 25: 160, 2009.

Hemipilia purpureopunctata in India – Agrawala et al. Type: China, SE Xizang (Tibet), Bomi, 2500 m, 19.07.1965, Y.T. Chang & K.Y. Lang 384 (holotype, PE-01432216). Specimen examined: Arunachal Pradesh, West Siang, Monigong, 1800 m, 03.06.2012, M. Bhaumik 27633 (ARUN!). Description (Fig. 1). Terrestrial herbs, 15-46 cm tall. Tubers ellipsoid, 2-4 × 1-1.5 cm. Stem erect, 16-40 cm tall, with 1 leaf at the base and 2-5 sterile scale-like bracts above, purple spotted throughout. Leaf solitary, elliptic to ovate-oblong, 5-14 × 3-5 cm, acute at apex, amplexicaul at base, light purple abaxially, greenish with purple spotted adaxially. Inflorescence 10-20 cm long, laxly 5-20-flowered; rachis and peduncle irregularly purple spotted. Pedicel with ovary 1-1.5 cm long, purple spotted. Flowers pink to pale purple, spotted with purple except at labellum. Dorsal sepal erect, oblong, concave, ca 5 × 2 mm, rounded, 3-veined, forming hood together with petals; lateral sepals ovate elliptic, ca 5 × 4 mm, obtuse. Petals ovate, concave, ca 5 × 4 mm, 3-veined. Lip sub-ovate in outline, 10-11 × 9-10 mm, 3-lobed at apex; lateral lobes oblong, broader and longer than mid-lobe, apical margin irregularly crenulate-undulate; mid-lobe ovate-oblong; spur 7-10 × 2-3 mm, with wide opening, curved outwards, abruptly swelled at apex. Anther sessile; rostellum trilobed; viscidia naked, situated above mouth of spur; pollinia 2, sectile. Capsules ellipsoid, ca 15 × 3 mm, with purple spots. Red List Assessment as per IUCN Criteria (IUCN, 2012a; 2012b; 2017): This species is known from India by the only specimen [M. Bhaumik 27633 (ARUN!)] from Arunachal Pradesh. Its distribution has been found as restricted to one population at Monigong area, West Siang district. There is no information available on its past population size and possible decline. If the geographic range (Fig. 2) is considered for its threat status assessment (Criteria B), the Extent of Occurrence (EOO) and Area of Occupancy (AOO) with standard grid size can be calculated as 4 sq.km. (Critically Endangered, B1 & B2). This species has very short aerial life span and hibernate through tubers during most part of the year. This could be a reason why this species has been escaped from peoples sight during floristic surveys. One of the authors [Manas Bhaumik] has observed the species in its natural habitat and he could find only 40-50 individuals growing in isolated patches. The species has not been observed by other floristic workers who have surveyed the area and other localities with

4 Fig. 1. Hemipilia purpureopunctata A. in its natural habitat; B. Close up view of leaf showing the purple spots; C. inflorescence [from M. Bhaumik 27633 (ARUN)] similar habitat. This indicates that this species is not a common one. The cause of its rarity need to be understood through more specific studies. Although, this species is not reported as traded or exploited for any purpose, it inhabits fragile habitat highly prone to natural calamities like land slide, avalanches etc. The flowers are resupinate with well-developed

Hemipilia purpureopunctata in India – Agrawala et al. Fig. 2. Distribution map of Hemipilia purpureopunctata A. Distribution in World; B. Localities in India and China. rostellum indicating cross pollination. The non-endospermic seeds require external nutrients for their germination. Due to the restricted distribution, rare occurrence, reproductive barriers and the declining quality of habitat,

6 the threat status in Indian perspective can be assessed as ‘Critically Endangered’ [CR B1ab(iii)+2ab(iii); D]. As the species is also reported from adjoining area in China (Tibet) sharing continuous suitable habitat for exchange/replenishment of germplasm, the threat status in Indian perspective can be downgraded to ‘Endangered’ [EN]. More exploration in adjoining areas to locate additional population is pre-requisite to understand the biology and life-cycle of this species. Habitat management and research are being recommended for its conservation in the natural habitat.

Acknowledgement Authors are thankful to the Director, Botanical Survey of India, and the Head of Office, BSI, SHRC for facilities and encouragement. Thanks are also due to the officials of Forest Department, Arunachal Pradesh for providing permission and help during the field work. The Ministry of Environment, Forests and Climate Change, New Delhi is thankfully acknowledged for financial assistance under Himalayan Research Fellowship scheme of National Mission on Himalayan Studies.

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