Journal of Threatened Taxa | www.threatenedtaxa.org | 26 March 2025 | 17(3): 26741–26743

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)

https://doi.org/10.11609/jott.8985.17.3.26741-26743

#8985 | Received 23 February 2024 | Final received 02 January 2025 | Finally accepted 05 March 2025

New distribution record of Korthalsia rogersii Becc, a threatened endemic climbing palm of Andaman archipelago

Paremmal Sarath ¹, Azhar Ali Ashraf ², V.B. Sreekumar ³, Modhumita Ghosh Dasgupta ⁴

& Suma Arun Dev ⁵

^1,5 Forest Genetics and Biotechnology Division, Kerala Forest Research Institute, Peechi, Thrissur, Kerala 680653, India.

¹ Forest Research Institute (Deemed to be University), Uttarakhand 248006, India.

² Department of Forestry, Sir Syed College, Taliparamba, Kerala 670142, India.

³ Forest Ecology and Biodiversity Conservation Division, Kerala Forest Research Institute, Peechi, Thrissur, Kerala 680653, India.

⁴ Division of Plant Biotechnology & Cytogenetics, ICFRE-Institute of Forest Genetics and Tree Breeding, R.S. Puram, Coimbatore, Tamil Nadu 641002, India.

¹ psarathparemmal@gmail.com, ² azharalia09@gmail.com, ³ vbskumar@gmail.com, ⁴ gmodhumita@gmail.com, ⁵ sumadev@rediffmail.com (corresponding author)

Editor: Vivek Pandi, Manipal Academy of Higher Education, Manipal, India. Date of publication: 26 March 2025 (online & print)

Citation: Sarath, P., A.A. Ashraf, V.B. Sreekumar, M.G. Dasgupta & S.A. Dev (2025). New distribution record of Korthalsia rogersii Becc, a threatened endemic climbing palm of Andaman archipelago. Journal of Threatened Taxa 17(3): 26741–26743. https://doi.org/10.11609/jott.8985.17.3.26741-26743

Copyright: © Sarath et al. 2025. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

Funding: Department of Biotechnology, Ministry of Science and Technology, Government of India

(No. BT/ PR 29212/ FCB/ 125/ 14/ 2018, 21.02.2019) & KSCSTE-Kerala Forest Research Institute.

Competing interests: The authors declare no competing interests.

Acknowledgements: The authors are thankful to the officials of Andaman & Nicobar Forest Department for the permission to carry out field expeditions in the reserve forests and protected areas. The financial support received from the Department of Biotechnology, Ministry of Science and Technology, Government of India (No. BT/ PR 29212/ FCB/ 125/ 14/ 2018, 21.02.2019) is gratefully acknowledged.

Sunda shelf holds a large number of palm species, also embraces a significant diversity of climbing palms (rattans) of the subfamily Calamoideae, which comprise eight genera (Baker et al. 2000; Vorontsova et al. 2016). Among these, the unique and conspicuous genus Korthalsia Blume (Arecaceae: Calamoideae: Calameae) has diversified with 28 species in the perhumid areas of Andaman & Nicobar Islands to New Guinea (Dransfield 1981). The Andaman archipelago harbors only two species of Korthalsia, the widespread K. laciniosa and the endemic species K. rogersii (Figure 1). The rest of the species are distributed across the Malesia region (Manohara et al. 2010; Shahimi 2018). Beccari (1918) used the type specimens of K. rogersii collected by C.G. Rogers from the South Andaman Islands in 1904 to describe the species; based on this specimen, Brandis (1906) also indicated the presence of the species in Andaman Island (Dransfield 1981; Mathew et al. 2007). Initially, the species was thought to be a miniature form of K. laciniosa. However, unique morphological characteristics of the species such as unarmed leaf sheath, ocera, slender & tementos rachilla and comparatively larger fruit size make the species morphologically more distinct from K. laciniosa and closer to K. concolor, a native species in Sabah, northern Borneo (Dransfield 1981). However, identification of the specimen of K. rogersii used for the study is provisional, the species has been found closer to K. lanceolata in the recent molecular systematics & evolutionary analysis (Shahimi 2018). A century after its initial collection, the species was again reported from Chidiyatapu, South Andaman in 1993 as part of the Flora India project. Further, living specimens of the species were relocated to the Jawaharlal Nehru Tropical Botanic Garden and Research Institute (JNTBGRI) and Kerala Forest Research Institute, Kerala, India, from its original location. Even though the species description was provided by Beccari (1918), Basu (1992); and Renuka & Vijayakumar (1995), it was based on the infertile specimen including rachilla. Renuka & Vijayakumar (1995) also reported that the species is differentiated from K. laciniosa. A description on the floral characteristics of the relocated living specimen flowered at JNTBGRI originally collected from Burmanallah, South Andaman were given by Mathew et al. (2007). Initially, the species was thought to be confined to Diglipur population, North Andaman, Havelock and Burmanallah/Chidiya Tapu, South Andaman population (Renuka & Vijayakumar 1995; Mathew et al. 2007; Manohara et al. 2010). However, the present study revealed four newly explored populations of the species spanning from North Andaman to South Andaman based on an expedition carried out across the Andaman Islands during 2022 (Figure 1).

The field survey was carried out across seven forest divisions covering the five major islands of Andaman and Ritchie’s archipelago. The populations of K. rogersii were identified from seven locations including the previously known locality (Table 1, Figure 1). The identity of the species is confirmed by following the general characteristics of the species (Box 1) and taxonomic key reported to differentiate the rattan species in Andaman & Nicobar Islands (Renuka & Vijayakumar 1995). The individuals encountered during the survey were restricted to fewer than 25 individuals in the majority of the populations. However, the populations at Chidiya Tapu and Interview Island were exceptions, where more than 30 individuals were recorded (Image 1). Most populations are distributed in evergreen and riparian habitats, with the species co-occurring alongside K. laciniosa, occupying a similar niche, except for the populations at Chidiya Tapu and Interview Island.

Consequently, we extended our survey to other areas where K. laciniosa is distributed (Saddle Peak, North Andaman; Prembukbay, Middle Andaman; Mount Harriet, Wandoor & Rutland Island, South Andaman; Little Andaman; Sir William Peel Island & Henry Lawrence Island, Ritchie’s archipelago), but we were unable to find K. rogersii in these areas. Though a population of the species has been located on Havelock Island in the Ritchie’s archipelago, we could not find the species in the nearby larger islands (Sir William Peel and Henry Lawrence Islands) of the archipelago. During our field visit in the months of April–May, we did not encounter any flowering/seed-bearing individuals, however, seedling recruitment was observed solely in Chidiya Tapu and Interview Islands (Images 2 & 3). It is noteworthy that despite the co-occurrence of K. rogersii and K. laciniosa in most populations, increased population size & seedling recruitment were evident in Chidiya Tapu and Interview Island populations, where K. laciniosa is notably absent. Furthermore, it would be intriguing to explore the impact of fragmented distribution of the species, along with its restricted population size and barriers to dispersal induced by the insular habitat, on gene flow and genetic structure of populations. This investigation holds significant implications for conservation of the species, which is further threatened by the extraction of canes.

Box 1. General description of the species based on Odoardo Beccari (1918); Basu et al. (1992); Renuka & Vijayakumar (1995) and Mathew et al. (2007).

Climbing aerially branching rattan with clustered, slender stem (0.7 cm in diameter), hapaxanthic, and hermaphroditic flowers. Pinnate leaves up to 1 m long with light green unarmed leaf sheath. Lower stem diameter & leaf size and absence of knee in the nodes. Ocrea is tightly sheathed without domatia. 15 cm long petiole armed below with 2 rows of recurved spins and with short cirrus. 13 x 6.5 cm cuneate-rhomboid, unevenly serrated, equidistant leaflets. Inflorescence 0.5 m long, with truncated secondary sheath and a tubular unarmed primary sheath. Inflorescence contains up to 3–5 cm long five rachillae. Flowers gamosepalous, broadly oval, and have a cup-shaped calyx with three (2 x 1) light brown sepals, and three fleshy boat-shaped petals (5 x 1 mm). Stamens 6, 3 + 3 dehisced abaxially and slightly inflexed toward the center. Tricarpellary with a pyramidal stigma and short style. Oblong fruits with a persistent calyx and stigma. Flowering time in September–November and fruiting in March–August.

Table 1. Locality records of Korthalsia rogersii from the Andaman archipelago.

Forest division	Island & Location	GPS	No. individuals
Diglipur	Radhanagar, North Andaman	13.3796 N, 92.9476 E	<20
Mayabunder	Interview Island	12.8969 N, 92.7130 E	>35
Middle Andaman	Beetapur	12.6169 N, 92.9161 E	<20
	Bakultala	12.5249 N, 92.8114 E
Baratang	Baratang Island	12.1028 N, 92.7641 E	<25
Havelock	Havelock Island, Ritchie's Archipelago	12.0111 N, 92.9578 E	<30
South Andaman	Chidiya Tapu	11.51643 N, 92.7154 E	>40

FOR FIGURE & IMAGES - - CLICK HERE FOR FULL PDF

References

Baker, W., J. Dransfield & T. Hedderson (2000). Phylogeny, character evolution, and a new classification of the Calamoid palms. Systematic Botany 25: 297–322. https://doi.org/10.2307/2666644

Basu, S.K. (1992). Rattans (Canes) in India, a monographic revision. Rattan information Center, Kepong, Kuala Lumpur, Malaysia.

Beccari, O. (1918). Asiatic palms, Lepidocaryeae, Part 3, The species of the genera Ceratolobus, Calospatha, Ptectocomia, Plectocomiopsis, Myrialepis, Zalacca, Pigafelta, Korthalsia, Metroxylon, Eugeissona. Annals of the Royal Botanic Garden, Calcutta 12(2): 1–231.

Dransfield, J. (1981). A synopsis of the genus Korthalsia (Palmae: Lepidocaryoideae). Kew Bulletin 36(1): 163. https://doi.org/10.2307/4119016

Manohara, T.N., E.L. Linto & C. Renuka (2010). Diversity and conservation of palms in Andaman & Nicobar archipelago. Biodiversity and Conservation 19(13): 3655–3666. https://doi.org/10.1007/s10531-010-9918-6

Mathew, S., M.V, Krishnaraj, A. Mohandas & P. Lakshminarasimhan (2007). Korthalsia rogersii Becc.- a vanishing palm of the Andaman Islands. Palms 51(1): 43–47.

Renuka, C. & T.T. Vijayakumaran (1995). A mannual of the rattans of the Andaman and Nicobar islands. Kerala Forest Research Institute, Peechi, India, 66–69 pp.

Shahimi, S. (2018). Systematics and evolution of the rattan genus Korthalsia Bl. (Arecaceae) with special reference to domatia. PhD Thesis. School of Biological Sciences, University of Reading.

Vorontsova, M.S., L.G. Clark, J. Dransfield, R. Govaerts & W.J. Baker (2016). World checklist of bamboos and rattans. INBAR Technical Report No. 37. Kew, 453 pp.