Description of two new species of Hellenia (Costaceae) from North-east India

· Articles
Authors

R. Kumar1, S.K. Singh2*, B.K. Sinha3 & S. Sharma4

1Botanical Survey of India, Arid Zone Regional Centre, Jodhpur, Rajasthan, India
2Botanical Survey of India, Eastern Regional Centre, Shillong, Meghalaya, India
3Botanical Survey of India, CGO Complex, Salt Lake City, Kolkata, West Bengal, India
4Botanical survey of India, Northern Regional Centre, Dehradun, Uttarakhand, India
rkpaliwalbsi@yahoo.com; sksbsinc@rediffmail.com; drbks2004@yahoo.co.in; sachinbsi2012@yahoo.com
*Corresponding author: S.K.Singh; email: sksbsinc@rediffmail.com

Abstract

Two new species, Hellenia meghalayensis R. Kumar, Sushil K. Singh & B.K. Sinha, sp. nov., and Hellenia paramjitii R. Kumar, Sushil K. Singh & Sachin Sharma, sp. nov., are described from North-east India.

Keywords Hellenia, Costaceae, North-east, India.

Introduction

Hellenia Retz. is a small genus of family Costaceae, represented by five species in the world namely, H. borneensis (A.D. Poulsen) Govaerts, H. globosa (Blume) S.R. Dutta, H. lacera (Gagnep.) Govaerts, H. sopuensis (Mass & H. Mass) Govaerts and H. speciosa (J. Koenig) Govaerts (WCSP, 2016), mainly distributed in Southeast Asia, Malaysia and New Guinea. Formerly, the species were treated under genus Costus L. in almost all the major work of family Costaceae, till the Specht and Stevenson (2006) who proposed a new generic name Cheilocostus C.D.Specht. based on phylogenetic studies. Govaerts (2013) recently treated the species under genus Hellenia Retz. and discussed taxonomic complexity associated with genus. The members of this genus are of little economic value, due in part to its non-aromatic oil content and low species distribution in Asia (Specht & Stevenson, l.c.). In India the genus is represented by 2 species i.e. H. speciosa and H. lacera (Rao & Verma, 1972, Sabu, 2006), both occur in North-east India.

During field explorations for documenting phytodiversity of the North Eastern region, the authors collected a plant from Shella, East Khasi Hills, Meghalaya in August 2009 and another one in September 2014 from buffer area of Murlen National Park (Khualen-Khawzawl), Champhai, Mizoram. Study of the vegetative and flowering characters of these specimens revealed two species of Hellenia that could not be matched with any taxa known under the genus. Hence we think the samples represent species unknown to science and are thus described here as new.

Taxonomic description

Hellenia meghalayensis R. Kumar, Sushil K. Singh & B.K. Sinha, sp. nov., Figure 1.

H. lacera (Gagnep.) Govaerts similar, differs in having hairy upper leaf surface, hairy calyx, greenish red bracts, smaller stature and a semi-dormant habit.

Type: INDIA. Meghalaya: East Khasi Hills, Shella, 6 August 2009, R. Kumar & S.K. Singh 104012 (holo & isotype: ASSAM).

Deciduous herb c. 1.5 m tall with several new and old stems; rhizome horizontal, tuberous, 1 – 2 cm thick, perennial, highly branched, yellowish green inside. Stem 1 – 1.5 m tall, spirally twisted, branching at higher nodes with secondary branching, branches breaking through leaf sheaths, base of the stem covered by sheaths for 60 cm or more, sheaths closed, 4 – 7 cm long, greenish purple, villous. Leaves spirally arranged on the stem, seasonally deciduous, attached to sheath by 3 – 5 mm long petiole, densely hairy, articulated at the junction; lamina 17 – 23 × 4 – 6.5 cm, oblong-acuminate, upper surface densely hairy, lower surface sparsely hairy, ligule 5 mm long, truncate, densely hairy with 5 mm long hairs on the margins. Inflorescence terminal, initially obovate, lengthening with age 3 – 6 × 3 – 5 cm, green, light pink at maturity; one or more basal involucral bracts with leaf-like appendages at their apices; bracts imbricate, concave, stiff, c. 3 × 2 cm, exposed portion red, hairy, apex acuminate, beaked; bracteoles stiff, open, single keeled, 1 – 1.5 × 0.5 cm, acute, green tinged with red, sparsely hairy. Flowers several at one time, large, white; calyx cylindric, 1.5 – 2 cm long, tri-dentate, densely hairy, lobes 5–7 mm long, acute, pink; corolla tube short, white; corolla lobes lanceolate, membranous, 3 cm long, margins incurved, pinkish white; labellum large, suborbicular, texture thin, folded, wrinkled, c. 4 × 5 cm, white with a yellow median band c. 1 cm from the throat, margin entire, irregular; stamen petaloid, 4 – 5 × 0.7 – 1.0 cm, white, dorsal side hairy, apex reflexed, yellow, acute, thecae linear, parallel, c. 8 mm long, yellow; style 3 – 4 cm long, filiform, stigma capitate or funnel form with small rounded dorsal appendage, 2 × 3 mm, glabrous; ovary 4 – 5 mm long, 7 – 9 × 3 – 4 mm wide, flattened, hairy, trilocular, ovules many in two rows, superposed, nectary in two hollows connected to a gland at the apex of the ovary. Capsule 3-angled, bright red with calyx intact.

Distribution: North-east India (Figure 3).

Ecology: This species grows in sandy, moist soil on exposed forest margin sites at c. 500 m elevation.

Flowering: July – September.

Etymology: The species is named after Indian State Meghalaya from where it was collected.

Notes: In comparison with H. lacera and H. speciosa the two other Hellenia spp. in Northeast India, H. meghalayensis is a plant with extreme hairiness on both leaf surfaces, bracts, calyx, bracteoles, and ovary, but none on the stigma. The new species is also distinct in its unusual semi-dormancy pattern. During the cool, dry season, growth ceases, the newest stems drop their leaves and the oldest stems die back. Coming out dormancy months later, the previous year’s new growth, which has remained viable, produces spiral branches and branchlets, a character which differentiates H. speciosa and H. lacera. H. lacera grown under similar environmental conditions dies back, becoming completely dormant, while C. meghalayensis mostly remains evergreen. Other key differences noted in the Table 1.

Table 1. Comparison of Hellenia species in North-east India.

Characters

H. speciosa

H. lacera

H. meghalayensis

H. paramjitii

Leafy Shoot Height Annual, 2 – 3 m Annual, 2 – 3 m Perennial, 1 – 1.5 m Perennial, c.3 m
Ligule Truncate, 15 – 20 mm; hairs 5 mm Truncate, 15 – 20 mm long; hairs 20 mm Truncate, 5 mm long; hairs 5 mm Truncate, 6 – 8 mm long; densely hairy; hairs 3 mm
Lamina c. 28 × 9 cm 20 – 40 × 5 – 7 cm 17 – 23 × 4 – 6.5 cm 16 – 20 × 3 – 4 cm
Lamina Surfaces Upper glabrous; Lower pubescent Upper glabrous; Lower pubescent Both surfaces hairy Upper glabrous; Lower villous
Bracts Red, glabrous or pubescent, apex acuminate, beaked Red, hairy, apex rounded, dilacerating Green-red, hairy, apex acuminate, beaked Light pinkish (exposed one), densely villous, Inner one greenish with purple tinged, apex acuminate, beaked
Bracteole Red, glabrous or pubescent slightly beaked Red, obtuse, densely hairy Green, obtuse, hairy Light pinkish, acute, densely hairy
Calyx Red, glabrous or pubescent Red, hairy Green, pink tip, densely hairy Pink, densely hairy, acute
Ovary 8 – 10 mm, glabrous 7 – 9 mm, hairy 7 – 9 mm, hairy 10 – 15 mm mm, villous
Stigma Hairy Hairy Glabrous Glabrous

Hellenia paramjitii R. Kumar, Sushil K. Singh & Sachin Sharma, sp. nov., Figure 2.

H. speciosa (J. Koenig) Govaerts similar, differs in having 6–8 mm long ligule, narrow leaf lamina, densely villous light pinkish bract, villous ovary and glabrous stigma.

Type: INDIA. Mizoram: Champhai, Buffer area of Murlen National Park (Khualen-Khawzawl), 15 September 2014, R. Kumar et al. 131402 (holo & isotype: ASSAM).

Deciduous herb c. 3 m tall with several new and old branched stems; rhizome horizontal, tuberous, 3 – 4 cm thick, perennial, highly branched, yellowish green inside. Stem 2 – 3 m tall, spirally twisted, branching at higher nodes with secondary branching, branches breaking through leaf sheaths, base of the stem is covered by hairy sheaths for 1.5 – 2 m or more, sheaths closed, 5 – 9 cm long, greenish–dull purple, villous. Leaves spirally arranged on the stem, seasonally deciduous, attached to sheath by a 4 – 6 mm long petiole, silky hairy, articulated at the junction; lamina 16 – 20 × 3 – 4 cm, linear-oblong, apex acuminate, upper surface glabrous, lower surface villous, ligule 6–8 mm long, truncate, densely hairy with 3 mm long hairs on the margins. Inflorescence terminal, initially obovate, lengthening with age, 5 – 9 × 2.5 – 6 cm, light pink; 2 – 3 basal involucural bracts, apex with a leaf-like appendage; bracts imbricate, concave, stiff, c. 3 × 1.2 cm, exposed portion light pinkish, densely villous, inner portion greenish with purple tinged, apex acuminate beaked; bracteoles stiff, comparatively elongated, open, single keeled, 1.5 – 2.5 × 0.8 cm, acute, light pinkish, densely hairy. Flowers several at one time, large, white; calyx cylindric, 2 – 3.5 cm long, tridentate, densely hairy, lobes 6 – 9 mm long, acute, pink; corolla tube short, white; corolla lobes lanceolate, membranous, 3 cm long, margins incurved, pinkish white; labellum large, suborbicular, texture thin, folded, wrinkled, c. 4 × 4.5 cm, white with a yellow median band c. 1.5 cm from the throat, margin entire, irregular; stamen petaloid, 2 – 3 × 0.5 – 0.7 cm, white, dorsal side hairy, apex reflexed, yellow, acute, thecae linear, parallel, c. 7 mm long, yellow; style 2 – 3 cm long, filiform, stigma capitate or funnel form with small rounded dorsal appendage, 1.5 × 2.7 mm, glabrous; ovary 1 – 1.5 cm long, 1 – 1.2 × 0.6 – 0.8 mm wide, flattened, villous, trilocular, ovules many in two rows, superposed, nectary in two hollows connected to a gland at the apex of the ovary. Capsule 3-angled, pinkish red with calyx intact.

Distribution: Northeast India (Figure 3).

Ecology: This species grows in sandy, moist soil on exposed forest margin sites at c. 700 m elevation.

Etymology: The species is named in honor of Dr. Paramjit Singh, Director Botanical Survey of India, Kolkata for his valuable contribution in the field of Plant taxonomy.

Flowering: August–September.

Notes: The species is closely related with H. speciosa but differs in having 6 – 8 mm long ligule, narrow leaf lamina, densely villous light pinkish bract, villous ovary and glabrous stigma and also distinct in its unusual semi-dormancy pattern. The new species also shows similarities with H. meghalayensis in habit and some other taxonomic characters but the latter distinctly differ in its height (1 – 1.5 m), broader lamina (both surface hairy), green obtuse bracteoles. Other key differences are noted in the Table 1.

Key to the Indian species

1a. Leafy shoot usually unbranched; ligule 15 – 20 mm long; bracts red; stigma hairy……………………………. 2

1b. Leafy shoot branched; ligule 5 – 8 mm long; bracts greenish or pink; stigma glabrous……………………….3

2a. Bracts glabrous or pubescent, apex acuminate; bracteole glabrous or pubescent, slightly beaked; calyx glabrous or pubescent; ovary glabrous …………….. H. speciosa

2b. Bracts hairy, apex rounded, dilacerate; bracteole densely hairy, obtuse; calyx red, sparsely hairy; ovary hairy……..H. lacera

3a. Both surfaces of leaf hairy; plants 1 – 1.5 m tall; bracteole green, obtuse; calyx green with pinkish tip……..H. meghalayensis

3b. Upper surface of leaf glabrous, lower villous; plants c. 3 m tall; bracteole light pink, acute; calyx light pink……….H. paramjitii

     

Acknowledgements

The authors are grateful to the Director, Botanical Survey of India, Kolkata for facilities and H.O.O. of BSI ERC, Shillong and Jodhpur for encouragement. Sincere thanks are also due to John Mood, Lyon Arboretum, University of Hawaii, U.S.A. for useful suggestion; and to the State

Forest Department, Meghalaya and Mizoram for extending logistic support during field visits.

References

Govaerts, R. 2013. Hellenia Retz., the correct names for Cheilocostus C.D. Specht (Costaceae). Phytotaxa 151(1): 63-64.

Rao, A.S. and Verma, D.M. 1972. Material towards a monocot flora of Assam–II (Zingiberaceae and Marantaceae). Bulletin of the Botanical Survey of India 14: 114-143.

Sabu, M. 2006. Zingiberaceae and Costaceae of South India. Indian Association of Angiosperm Taxonomy, Calicut, Kerala, India. pp. 251-263.

Specht, C.D. and Stevenson, D.W. 2006. A new phylogeny-based generic classification of Costaceae (Zingiberales). Taxon 55: 153-163.

WCSP 2016. ‘World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://apps.kew.org/ wcsp/ Retrieved 30.05.2016.

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