A new species of Crepidium (Orchidaceae) from Meghalaya, North-east India

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Authors

S.K. SINGH*, M. MURUGESAN & A.A. MAO
Botanical Survey of India, Eastern Regional Centre, Shillong, Meghalaya, India.
*Corresponding author: S.K.Singh; email: sksbsinc@rediffmail.com

Abstract

A new species, Crepidium meghalayensis M. Murugesan, Sushil K.Singh & A.A. Mao is proposed here, based on a recent collection from the Khasi hills (Ri-Bhoi district), Meghalaya, India.

Keywords Orchidaceae, Crepidium, new species, Khasi Hills, India.

Introduction

The Crepidium Blume, remained under the cosmopolitan genus Malaxis Sol. ex Sw. until re-established by Szlachetko (1995). He has included about 167 species under Crepidium containing most of the Asiatic species of Malaxis. At present the genus is represented with c. 280 species found throughout the Asian tropics and sub tropics, Australasia and Indian ocean Islands with a few species in temperate Asia. The members of the genus are terrestrial or lithophytic and characterized by terminal, elongated inflorescence which bears many small nonresupinate flowers; the sessile labellum concave at the centre, with a membrane surrounding the cavity and large basal auricles. Fourteen species are recorded so far in India (Vij et al., 2013) with maximum distribution in North-east India (10-11 species).

During a recent field exploration to the forests of Meghalaya, the authors came across a small population of Crepidium species growing in the community reserve forests of Ri-Bhoi district, Khasi hills, Meghalaya. The study of vegetative and flowering plant revealed a species that could not be matched with any known species under the genus, hence, the same has been described here as a new species.

Crepidium meghalayensis M. Murugesan, Sushil K.Singh & A. A. Mao, sp. nov. (Figure 1).

Closely allied with Crepidium purpureum (Lindl.) Szlach., but differs in having plants up to 55 cm high; leaves 4 – 5(-6), well developed 10 – 24 cm long and 2.5 – 9 cm wide, (5-)7 – 9- ribbed, ovate-elliptic or ellipticlanceolate and often 1 – 3 reduced leaves; peduncle 4 (-5)-angled, 18 – 47 cm long, winged at base; sterile bracts 2 – 4 (5); floral bracts 6 – 13 mm long; flowers purple – dark purple, 11 –15 mm across; pedicel and ovary 10 – 17 mm long; labellum comparatively larger (8 – 10 × 6 – 7 mm), broadly orbicular-ovate, convex, constricted just below to the middle portion, base 2-lobed, obtuse, overlapping or rarely dilated.

Type: India, Meghalaya, Ri-Bhoi district, Kbet Nongbri village near Nongpoh, on soil covered rocks, 02.07.16, longitude 25°54’34″ N, latitude 92°0’50″ E, 840 m asl, S.K. Singh et al. 110483(Holo & Isotypes: ASSAM).

Terrestrial or lithophytic herb, 23 – 55 cm high including inflorescenece. Stem stout, glabrous, 7 – 10 cm high, sheathing at base, slightly pseudobulbous. Roots fasciculate, slender, up to 2.5 mm wide, appearing from the basal nodes of pseudobulbs. Pseudobulbs 1 – 1.5 × 0.5 – 1 cm, ovoid, underground, sheathing by 2 – 5 basal scales and leaf-bases, whitish. Leaves 4 – 5 (- 6), and 1 – 2 (3) reduced leaves, ovate-elliptic or ellipticlanceolate, 10 – 24 × 2.5 – 9 cm, 7 – 9-ribbed, narrowed to sheathing at base, acute or very shortly acuminate at apex, slightly-distinctly undulate at margin, petiolate or rarely sessile; leaf sheath 0.7 – 1.5 cm in diameter, more or less rigid; leaf petiole 2.5 – 4 × 1.2 – 1.7 cm, prominently abbreviated. Inflorescence raceme, 18 – 47 cm long, dark purplish; peduncle 15 – 40 cm long, 1 – 3 mm in diameter, 4 (-5) – angled, slightly winged at base and prominently ribbed towards apex; rachis 10 – 35 cm long, many-flowered, flowers laxly arranged at base of the inflorescence and dense towards apex. Sterile bract 2 – 5 in numbers, 3 – 7 × 0.5 – 1.5 mm, lanceolate, apex acute-acuminate, deflexed. Floral bracts numerous, 6 – 13 × 1 – 2 mm, usually longer than ovary, narrowly lanceolate or linear lanceolate, apex acuminate, green-purplish, deflexed. Flowers 1.1 – 1.5 cm across, slightly convex, dark-purplish. Sepals subsimilar, oblong, subacute-obtuse or rarely rounded at apex; dorsal sepal 6 – 7 × 1.5 – 2 mm, oblong or lanceolate, subacute-obtuse at apex, margin involuted, 3-nerved; lateral sepals 4 – 5 × 2 – 3 mm, broadly oblong-ovate – triangular-ovate, subacute or obtuse at apex, margin involuted, 3-nerved. Petals 5 – 6 × 0.8 – 1.1 mm, linear or linear-lancolate, obtuse or rarely truncate at apex, margin involuted. Labellum longer than sepals and petals, convex, fleshy, broadly orbicularovate, 8 – 10 × 6 – 7 mm when flattened, constricted just below to the middle portion, base divided in to 2 oblong lobes, slightly incurved at apex, auricles overlapping rarely dilated. Column fleshy, 1.5 – 2 mm long. Pollinia 2-paired, broadly obovate – falcate, 0.5 – 0.7 × 0.2 – 0.25 mm, yellow colored. Ovary and pedicel 1 – 1.7 cm long, often tinged with purple, linear-fusiform, ridged.

Distribution and ecology: The flowering plants of this species were growing along the undisturbed forests edges, on soil covered moist rock at an altitude of 840 m. The population consisted of 6 –7 individuals found in vicinity of Arisaema spp., Gastrochilus incospicuous (Hook.f.) Kuntze, Impatiens spp., Fimbristylis spp., Huperzia squarrosa (G. Forst.) Trev., etc.

Etymology: Named after the Indian state of Meghalaya from where the type is based.

Notes and differentiation: The new species show affinities with Crepidium purpureum (Lindl.) Szlach., Crepidium acuminatum (D.Don) Szlach. and Crepidium khasianum (Hook.f.) Szlach.. However, these species are quite distinct in having comparatively smaller plants (upto 30 cm high), leaves 5-7-ribbed, smaller inflorescences (upto 28 cm high) smaller pedicel and ovary which is up to 10 cm long (table 1). Crepidium purpureum further differs in having smaller peduncle (9-14 cm long), flowers yellowish-green tinged with purple, labellum oblong-ovate, 7-9 mm long, convex, constricted below to middle portion, apex deeply bilobed, truncate-obtuse and base often dilated Crepidium acuminatum differ from the species in discussion by its yellowish-green often tinged with purplish flowers, labellum broadly ovate or concave, entire margined which apex are notched or rounded or shallowly bilobed and base 2-lobed with dilated auricles. While Crepidium khasianum differs in its concave, smaller flowers (5-7 mm across), purplish sepals and petals and yellowish-green labellum (Table 1).

Table 1: Comparison of new species with the allied species:

Characters

C. khasianum

(Hook.f.) Szlach.

C. acuminatum

(D.Don) Szlach.

C. purpureum

(Lindl.) Szlach.

C. meghalayensis sp. nov.

Plant length 20-30 cm high 14-30 cm high. up to 30 cm high 23-55 cm high.
Leaves 4-5, ovate-elliptic or ovate-lanceolate, slightly oblique, greenish-grey flushed with purple, 4-9.5 × 1.5-4 cm, 5-7-ribbed 3 or 4, ovate-lanceolate, greenish, 5.5-12 × 2.5-6 cm, 5-7-ribbed 3-4, ovate-lanceolate, greenish, 7-18 × 4-5 cm, 5-7-ribbed 4-5(-6), ovate-elliptic or elliptic-lanceolate, greenish, 10-24 × 2.5-9 cm, (5)7-9- ribbed
Inflorescence raceme, peduncle 7-16 cm long, deeply ridged; rachis 4-5 cm long raceme, peduncle 13-28 cm long,  ribbed; rachis 4-8 cm long raceme, peduncle 9-14 cm long, ribbed; rachis 4-10 cm long raceme; peduncle 18-47 cm long, 4 (5)-angled and winged at base and ribbedtowards apex; rachis 10-35 cm long
Floral bracts lanceolate, acute at apex, reflexed, 7-7 × 1-1.5 mm lanceolate, subacute at apex, 3-4 × 0.5-1 mm lanceolate, acuminate at apex, reflexed, 6-7 × 1-1.5 mm lanceolate or linear-lanceolate,  acuminate at apex, reflexed, 6-13 × 1-2 mm
Flowers 5-7 mm across, sepals and petals purple,labellum yellowish-green 10-13 mm across, uniformly yellowish-green tinged with red-purple or pink-purple 14-16 mm across, yellowish-green, tinged with red-purple or pink-purple 11-15 mm across, purple-dark purple
Labellum oblong-ovate or triangular-ovate, concave, 2.5-3 × 1.5-2 mm, constricted below to mid portion; apex broad – transversely oblong, truncate, base 2-lobed, auricles dilated broadly ovate or ovate-sagittate, concave, 6-7 × 4-5 mm, not constricted; apex notched or rounded or shallowly bilobed; base 2-lobed, auricles dilated oblong-ovate, 7-9 mm long, convex, constricted below to mid portion; apex deeply bilobed, truncate-obtuse; base 2-lobed, auricles overlapping or often dilated broadly orbicular-ovate, 8-10 × 6-7 mm, convex, constricted below to mid portion; apex deeply bilobed, obtuse; base 2-lobed, auricles overlapping
Pedicel and ovary 3-5 mm long 5-7 mm long 8-10 mm long 10-17 mm long

Source: Seidenfaden (1978), Pearce & Cribb (2002), Kataki (1986); and our own observations

 

Acknowledgements

Authors are thankful to The Director, Botanical Survey of India, Kolkata for facilities and encouragement. Authors are also thankful to Mr Arul, DCF Wildlife Meghalaya and Villagers of the Kbet Nongbri for their help and support during field exploration.

References

Kataki, S.K. 1986. Orchids of Meghalaya. Govt. of Meghalaya, Shillong.

King, G. and Pantling, R. 1898. The orchids of the Sikkim-Himalaya. Annals of the Royal Botanic Garden, Calcutta Vol. VIII. 1-342 +133 plates.

Pearce, N.R. and Cribb, P.J. 2002. Flora of Bhutan: Including a record of plants from Sikkim and Darjeeling Vol.3 part 3. The orchids of Bhutan. Royal Botanic Garden Edinburgh, Rroyal Government of Bhutan.

Pridgeon, A.M., Cribb, P.J. Chase, M.W. and Rasmussen, F.N. 2005. Genera Orchidacearum Vol 4 Epidendroideae (Part One), Oxford Univ Press, New York.

Seidenfaden, G. 1978. Orchid genera of Thailand VII: Oberonia Lindl. & Malaxis Sol. ex Sw. Dansk Botanisk Arkiv 33(1): 1–94.

Szlachetko, D.L. 1995. Systema Orchidalium. Fragmenta Floristica et Geobotanica, Supplement 3: 123–133.

Vij, S.P., Verma, J. and Sathish Kumar, C. 2013. Orchids of Himachal Pradesh. Bishen Singh Mahendra Pal Singh, Dehradun.

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