Article
Phalaenopsis arunachalensis sp. nov. (Orchidaceae: Epidendroideae: Aeridinae) - A new epiphytic orchid from Arunachal Pradesh, Northeast India
Phalaenopsis arunachalensis sp. nov. (Orchidaceae: Epidendroideae: Aeridinae) - A new epiphytic orchid from Arunachal Pradesh, Northeast India
Lankesteriana, vol. 20, no. 3, pp. 275-280, 2020
Lankester Botanical Garden, University of Costa Rica
Received: 13 August 2020
Accepted: 30 September 2020
Abstract: A new epiphytic Phalaenopsis is described from tropical evergreen forests of Ziro Valley in Arunachal Pradesh, India, and illustrated with colored photos. It is allied to the similarly colored P. taenialis (Lindl.) Christenson & Pradhan in having non-deciduous leaves, larger perianth segments, the shorter and convex (not flat) lip mid-lobe, and the yellowish-green (not purplish) spur. The new species is morphologically most similar to P. honghenensis from China, but differs most easily by the light pinkish flowers versus bronzy green to brownish flowers of the latter species. A detailed description with corresponding color photos and information on the habitat is provided. The voucher specimens have been deposited at the Herbarium of the Orchid Research Centre Tippi, Arunachal Pradesh, and the Herbarium of The Orchid Society of Eastern Himalaya (TOSEHIM), Regional Orchid Germplasm Conservation and Propagation Centre (Assam Circle), Assam.
Key Words: Flora of India, new Phalaenopsis, Phalaenopsis honghenensis, Phalaenopsis subgen. Aphyllae, Phalaenopsis taenialis.
Introduction
The genus Phalaenopsis Blume was first described by Carl Ludwig Blume in 1825. The genus is represented by a total of 97 species and is widely distributed across Southeast Asia (South India, Sri Lanka, southern China to Taiwan, Indonesia, Thailand, Myanmar, Malaysia, the Philippines, Papua New Guinea) and northern Australia (Govaerts et al. 2020). Whereas Sweet (1980) initially listed 47 species for the genus and Christenson (2001) listed 62 entities. In India the genus is represented by 12 species (Misra 2019) distributed throughout the Himalayas, Peninsular India and Andaman and Nicobar islands and only four of them were recognized in Arunachal Pradesh (Rao 2010) viz. Phalaenopsis deliciosa Rchb.f., P. mannii Rchb.f., P. lobbii (Rchb.f.) Sweet, and P. taenialis (Lindl.) Christenson & Pradhan. So far, there have been a much of complexity associated with the subgen. Aphyllae where our new species belongs and has been dealt by Dalström et al. (2010) where much of the problems involving P. taenialis complex were largely resolved.
On 15 October, 2019, during a field trip to the forested area of Ziro Valley of Lower Subansiri district of Arunachal Pradesh, the first author collected an epiphytic orchid. It was subsequently planted along an orchid trail located in the Tale Wildlife Sanctuary, Ziro Valley of Arunachal Pradesh, and flowered under observation in March, 2020. Comparing it with the available literature (Hooker 1890, 1894, King & Pantling 1898, Pradhan 1979, Chowdhery 1998, Pearce & Cribb 2002, Lucksom 2007, Chen et al. 2009, Rao 2010, Dalström & Ormerod 2010, Dalström et al. 2010, Hegde 2017, Swami 2017, Gogoi 2019, Gruss 2020) and critical examination of herbarium specimens deposited in ASSAM, ARUN, CAL, as well as with type images present in K, E and PE, it was confirmed that this orchid represented an hitherto undescribed Phalaenopsis species. Hence, it is described below as new.
Taxonomic treatment
Phalaenopsis arunachalensis K.Gogoi & Rinya sp. nov.
TYPE: India. Arunachal Pradesh: Lower Subansiri, Ziro, 1400 m, 16 October 2019, fl. 15 April 2020, K. Gogoi and K. Rinya 00809 (Holotype: OHT; Isotypes: ASSAM, TOSEHIM). (Fig. 1-3).
Diagnosis: Phalaenopsis arunachalensis differs from the similarly colored P. taenialis (Lindl.) Christenson & Pradhan in having non-deciduous leaves, larger perianth segments, shorter and convex (not flat) lip mid-lobe and yellowish-green (not purplish) spur. The new species also differs from the similarly shaped P. honghenensis F.Y.Liu by the pinkish flowers versus bronzy green or brownish flowers in the latter species. The differences between P. arunachalensis and P. taenialis are shown in Table 1.
Herb epiphytic. Roots flattened, minutely warty, young roots silvery with green and maroon root caps. Stems to 1 cm, 2 or 3-leaved. Leaves obliquely elliptic, 5-10 × 2.5-3.5 cm, acute at apex, sheathing bases persistent, spotted purple-red. Inflorescence suberect to pendent, racemose, to 21.5 cm, laxly 5-6-flowered; peduncle ca. 10 cm long; rachis ca. 11.5 cm long; floral bracts ovate, to 6 mm. Flowers to 3.0-3.2 cm across, sepals and petals rose-pink, lip purple; pedicel and ovary 3.2-3.5 cm. Dorsal sepal oblong-elliptic, 1.5-1.6 × 0.8 cm, obtuse. Lateral sepals obliquely elliptic-ovate, ca. 1.5 × 0.9 cm, obtuse. Petals spathulate, ca. 1.5 × 0.8 cm, obtuse. Lip minutely spurred, trilobed; lateral lobes oblong, ca. 9 × 2 mm, obliquely truncate; mid-lobe oblong, ca. 9 × 4 mm, tapered at both ends, apex obtuse. Spur cylindric-conical, 2 mm long. Callus biseriate: posterior callus fleshy, bifid, terminating at base of mid-lobe; anterior callus plate like, bifid, extending beyond base of mid-lobe. Column to 9 mm long, stout, conspicuously dilated to either side of stigma, foot 2-3 mm. Pollinia 4, sub-globose, yellow. Seed pods and seeds not seen.
Examined material
India. Arunachal Pradesh: for- ested area of Ziro Valley of lower Subansiri district, 16 October 2019, fl. 15 April 2020 in the Tale Wildlife Sanctuary, K. Gogoi and K. Rinya 00809
Flowering period
March to April.
Habitat
On tree trunks in sub-tropical evergreen forest at 1200-1400 m in Ziro, Arunachal Pradesh.
Distribution
India (Ziro, Arunachal Pradesh).
Etymology
The specific epithet refers to the state of Arunachal Pradesh, in Northeast India, from where the new species was collected.
Figure 1
A. Distribution map of Phalaenopsis arunachalensis. B. Natural habitat of P. arunachalensis. C. Phalaenopsis arunachalensis in natural habitat showing close up of inflorescence.
Photos by K. Gogoi.
Figure 2.
Phalaenopsis arunachalensis.
. Habit.B. Flower, side view.C. Flower, ventral view.D. Perianth, ventral view.E. Perianth, dorsal view.F. Lip with ovary and column.G. Lip, side view.H. Lip, ventral view.I. Lip, longitudinal section.J. Ovary with pedicel and column.K. Column, front view.L. Anther cap with pollinia, ventral view.M. Anther cap, ventral view.N. Anther cap, dorsal view.O. Pollinarium, ventral view.P. Pollinarium, dorsal view.Photos by K. Gogoi.
Figure 3.
Phalaenopsis arunachalensis.
A. Habit.B. Flower, side view.C. Flower, ventral view.D. Perianth, ventral view.E. Perianth, dorsal view.F. Lip with ovary and column.G. Lip, side view.H. Lip, ventral view.I. Ovary with pedicel and column.J. Column, front view.K. Anther cap with pollinia, ventral view.L. Anther cap, ventral view.M. Anther cap, dorsal view.N. Pollinarium, ventral view.O. Pollinarium, dorsal view.Drawing by K. Gogoi.
Acknowledgements
The authors are grateful to Dr. Pankaj Kumar, Kadoorie Farm and Botanic Garden (KFBG) Corporation, Lam Kam Road, Tai Po, New Territories, Hong Kong S.A.R., China; Olaf Gruss, In der Au 48, 83224, Grassau, Germany, and Stig Dalström, Lankester Botanical Garden, University of Costa Rica, Cartago, Costa Rica for providing literature and valuable suggestions for the identity of the species. The authors are also thankful to Dipanker Bora, Rajib Gandhi University, Arunachal Pradesh and Department of Environment and Forest, Government of Arunachal Pradesh (India) for their cooperation.
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