A new species of Argyreia (Convolvulaceae) from the southern Western Ghats, India

A new species of Argyreia (Convolvulaceae) from the southern Western Ghats, India Yadav P.B.S.1, Karuppusamy S.1*& P.S.S. Richard2 1Department of Botany, Botanical Research Centre, The Madura College (Autonomous), Madurai – 625011, Tamil Nadu, India (Affiliated with Madurai Kamaraj University) 2Department of Botany, Madras Christian College (Autonomous), Tambaram, Chennai – 600059, Tamil Nadu, India *E-mail: [email protected] Abstract: Argyreia manjolaiensis (Convolvulaceae), a new species from the southern Western Ghats of Tamil Nadu, is described and illustrated. Detailed description, photoplates, and distribution map are provided. Information on population status and ecology is also presented to facilitate the identification and conservation of the species. Keywords: Endemic species, Morning glory, Tamil Nadu, Taxonomy Arisdason & D. Maity (Shalini et al., 2020) and A. sharadchandrajii Lawand & Shimpale (Lawand & Shimpale, 2021). A recent molecular phylogenetic study on the genera Argyreia and Ipomoea (Muñoz-Rodríguez et al., 2019) suggested the merging of Argyreia under Ipomoea. However, both genera have already been well established as distinct entities by several authors (Clarke, 1883; Cooke, 1908; Ooststroom & Hoogland, 1953; Lawand, 2019; Shalini et al., 2020; Lawand & Shimpale, 2021). In light of this, we have chosen to follow the traditional classification, treating Argyreia as a separate genus. This distinction is supported by clear morphological differences and a number of prominent features that differentiate Argyreia from its allied genera (Lawand & Shimpale, 2021). Additionally, the two genera are clearly separated by their geographical distribution and cytogenetic evidences (Sampathkumar & Ayyangar, 1981; Mabberley, 2018). Materials and Methods During the floristic explorations of the southern Western Ghats of Tamil Nadu in India, the authors collected some interesting specimens of the genus Argyreia from Manimuthar waterfalls, on the way to Manjolai, Tirunelveli district, Tamil Nadu. The specimens were examined using relevant taxonomic literatures (Hooker, 1885; Gamble, 1925; Karthikeyan et al., 2009; Nayar et al., 2014; Lawand et al., 2019; Shalini et al., 2020; Lawand & Shimpale, Received: 18.09.2024; Revised & Accepted: 08.11.24 Published Online: 31.12.2024 Introduction The genus Argyreia Lour. (Convolvulaceae) is native to continental Asia, almost all taxa primarily distributed across the tropical and subtropical regions of southeast Asia, China, and the Indian subcontinent, comprising approximately 143 species (Staples & Traiperm, 2017; Traiperm & Suddee, 2020; POWO, 2024). Among these, only four species are confined to Madagascar with disjunct distribution (Deroin, 2001). In India, the genus is represented by 40 species of which 17 are endemic (Lawand, 2019; Lawand et al., 2019). A total of 24 taxa have been reported from the Western Ghats among which13 are endemic to the region (Nayar et al., 2014). Recently, Lawand et al. (2019) conducted a taxonomic revision of Argyreia from India. Since then, couple of new species were described from the Western Ghats of India: A. lakshminarasimhanii S. Shalini, Sujana, Vol. 34(5): 483–487 (2024) ISSN: 0971-2313 (Print edition) ISSN: 2582-2438 (Online edition) https://dx.doi.org/10.22244/rheedea.2024.34.05.09 Rheedea Journal of the Indian Association for Angiosperm Taxonomy RESEARCH ARTICLE 484 A new species of Argyreia from India Taxonomic treatment Argyreia manjolaiensis Karupp., Bharath & P.S.S.Rich., sp. nov. Fig. 1 & 2 Morphologically similar to A. fulgens Choisy but can be easily distinguished from 2–2.5 cm long petiole (vs. 3–7 cm long), a cordate lamina base (vs. rounded), a hairy abaxial surface of the lamina (vs. glabrous), 12 secondary veins (vs. 18–22), 10–12-flowered inflorescence (vs. 5–7-flowered), 3 bracts (vs. 2), subequal or unequal sepals (vs. equal) and a corolla tube that is pale purple at the base and milky white at the throat (vs. dark purple throughout). A detailed morphological comparison is provided in Table 1. Type: INDIA, Tamil Nadu, Tirunelveli, Manimuthar falls, on the way to Manjolai, above 684 m, 20.08.2023, Karuppusamy, Bharath & Richard 3121 (holo SGH!; iso MCCH! MH!). A woody climbing shrub, grows up to 24 m or more. Stems terete, green, sericeous. Leaves dorsiventral, alternate; petioles terete, 2–2.5 cm long, green, sericeous as in stem, shallowly grooved; lamina ovate, 5.6–6.8 × 4–4.5 cm, base cordate, apex acute to acuminate, margins entire, ciliate, partially hairy adaxially, densely silvery shiny tomentose abaxially, secondary veins 12 pairs, raised prominently below. Inflorescence an axillary, 10–12-flowered, capitate cyme; peduncles 2.5 cm long, green, hairy like stem, slightly longer than petioles. Bracts 3; outer bract oblonglanceolate, 2–2.5 × 0.6 cm; inner two lanceolate or falcate, 1.5–1.8 × 0.4 cm, densely sericeous outside, except overlapped areas, hairy inside, minutely 5–9 veined inside, margins entire, apex acute. Flowers subsessile; pedicels c. 0.2 cm long, hairy. Sepals 5, ovate-lanceolate, subequal or unequal; outer two narrow, 1–1.2 × c. 0.4 cm; inner three broad, c. 0.6 × 0.5 cm, margins entire, hyaline, apex acute, glabrous inside, sericeous all over outside except overlapped areas. Corolla infundibuliform, c. 5 cm long, c. 5 cm across, purple at the base, milky white near throat; tube dark purple inside, hairy on mid-petaline bands. Stamens 5, unequal, 3 short, 2 long; longer stamens c. 1.5 cm long; shorter stamens 0.8–1 cm long; filaments white, 2021) but could not be identified. Therefore, the specimens were compared with type specimens and digital images in online herbaria databases (CAL, CALI, E, GDC, K, L, LINN, MH, P and SGH). After critical observations on specimens deposited at all above herbaria, it is concluded that the present species does not match with any described species of the genus Argyreia hence, it is described here as new. Detailed morphological observations were recorded and described using terms of Beentje (2016). The herbarium specimens were prepared and deposited in the SGH, The department of Botany, The Madura College, Madurai. Authors have generated the distribution map using QGIS ver. 3.32.3 (QGIS Development Team, 2022), based on geocoordinates of collection localities. The Area of Occupancy (AOO) and Extent of Occurrence (EOO) were estimated using GeoCAT (Bachman et al., 2011), and a provisional conservation status was assessed according to the IUCN Red List Categories and Criteria (IUCN, 2024). Fig 2 . Map showing the distribution of Argyreia manjolaiensis Karupp. Bharath & P.S.S.Rich. (Map prepared by P. Bharath Simha Yadav using QGIS 3.32.3). 485 Yadav et al. Fig. 1. Argyreia manjolaiensis Karupp., Bharath & P.S.S.Rich.: a . A flowering twig; b . Leaf–abaxial view; c . Leaf–adaxial view; d . Leaf abaxial surface–Closeup view; e . Leaf–tip; f . Inflorescence; g . Bracts; h . Flower–frontview; i . Sepals; j . Flower–side view; k . Flower cut open showing stamens and pistil; l . Stamens; mPistil (Photos P.S.S. Richard) 486 A new species of Argyreia from India 486 with few glandular trichomes at the base; anthers basifixed, c. 0.4 cm long. Ovary ovoid-ellipsoid, pale green, encircled by annular ring; style single, c. 1 cm long; stigma biglobose, white. Fruit a globose berry, 1.5–2 cm across, topped by remnant of style base, yellow when ripened. Seeds 4, ellipsoid to obovoid, 1.5–2 × 3.5–6 mm, white, glabrous. Flowering & Fruiting: Flowering from July to September; fruiting from August to November. Ecology: The species occurs in tropical dry deciduous and semi-evergreen forests at elevantions of 450–600 m, inhabiting exposed areas of the forests and climbing over trees. Some of the associated taxa include Nothopegia heyneana (Hook.f.) Gamble, Semecarpus anacardium L.f. (Anacardiaceae), Careya arborea Roxb. (Lecythidaceae), Cleistanthus travancorensis Jabl. (Phyllanthaceae), Filicium decipiens (Wight & Arn.) Thwaites (Sapindaceae), Grewia tiliifolia Vahl (Malvaceae), Capparis diversifolia Wight & Arn. (Capparaceae), Strobilanthes parvifolia J.R.I.Wood (Acanthaceae), Eugenia calcadensis Bedd. (Myrtaceae), Terminalia anoegeissiana Gare & Boatwr. (Combretaceae), and Tectona grandis L.f. (Verbenaceae). Distribution: Presently known only from the type locality of Manimuthar waterfalls, on the way to Manjolai, Tirunelveli district, Tamil Nadu, India (Fig. 2). Etymology: The new species is named after the type locality, Manjolai estate in KalakaduMundanthurai Tiger Reserve of southern Western Ghats. Conservation status: Fewer than 25 mature individuals of Argyreia manjolaiensis, with an extent of occurrence (EOO) of 30 km2, area of occupancy (AOO; AOO based on user defined cell width [3 km]) 63 km2 have been found at the type locality. According to the latest IUCN conservation status assessment guidelines (IUCN Standards and Petitions Committee, 2024 ver. 2024-1), Argyreia manjolaiensis is provisionally assessed here as Critically Endangered (CR). Acknowledgments The authors extend their gratitude to the Head of Office, Botanical Survey of India, Southern Regional Circle, Coimbatore, for granting permission to consult the herbarium and library. Special thanks are due to Dr. V. Ravichandran (Southern Regional Circle, Coimbatore, BSI), Dr. R.K. Singh and Table 1. Comparison of morphological characters between Argyreia manjolaiensis and A. fulgens Characters A. manjolaiensis sp. nov. A. fulgens Choisy Petioles 2–2.5 cm long, without any glands 3–7 cm long, with two protuberances like glands at point of attachment with lamina Lamina Cordate at base; hairy abaxially Rounded at base; glabrous Secondary veins 12, green in young leaves 18–22, purple in young leaves Inflorescence Capitate cyme, 10–12-flowered Dichotomously branched cyme, 5–7-sflowered Peduncles Equalling or longer than petioles Shorter than the petioles Bracts 3, oblong-lanceolate 2, linear-oblong Sepals Subequal or unequal, 1–1.2 × 0.4 – 0.5 cm Equal, 0.5–0.7 × c. 1 cm Corolla c. 5 cm long, 5 cm across; tube purple at the base, throat milky white 2.5–3.5 cm long, 2–2.5 cm across; tube purple throughout 487 Yadav et al. Dr. A. Ravikiran (Arid Zone Regional Centre, Jodhpur, BSI), for their valuable comments on the identity of the new species; Ms. K. Sonali, Research Scholar, Department of Botany, M.H. Shinde Mahavidyalaya, Tisangi, Maharashtra, for the assistance in obtaining references and the curators of BSI, CAL and K for providing digital images of type specimens. Authors are also thankful to the forest officials of Tamil Nadu, for the necessary permissions to conduct the field work. Literature Cited BACHMAN S., MOAT J., HILL A.W., DE LA TORRE J. & B. SCOTT 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. In: SMITH V. & L. PENEV (eds.), e-infrastructures for data publishing in biodiversity science. ZooKeys 150: 117–126. https://doi. org/10.3897/zookeys.150.2109 BEENTJE H. 2016. The Kew plant glossary: an illustrated dictionary of plant terms. Second edition. Kew Publishing, Royal Botanic Gardens, Kew. CLARKE C.B. 1883. Convolvulaceae. In: HOOKER J.D. (ed.), The flora of British India. .Volume 4. L. Reeve & Co., London. pp. 179–228. COOKE T. 1908. Flora of the Presidency of Bombay. Volume 2. Taylor & Francis, London. DEROIN T. 2001. Convolvulaceae. In: MORAT P. (ed.), Flore de Madagascar et des Comores 171: 11–287. GAMBLE J.S. 1925. Flora of the Presidency of Madras. Volume 2(7). Adlard & Sons Ltd., London. HOOKER J.D. 1885. The Flora of British India. Volume IV. L. Reeve & Co., London. IUCN 2024. The IUCN Red List of Threatened Species. Version 2024-1. Available at: https://www. iucnredlist.org. (Accessed on 05.09.2024). KARTHIKEYAN S., SANJAPPA M. & S. MOORTHY 2009. Flowering Plants of India Dicotyledons, Volume 1 (Acanthaceae – Avicenniaceae). Botanical Survey of India, Kolkata, p.365. LAWAND P.R. & V.B. SHIMPALE 2021. Argyreia sharadchandrajii (Convolvulaceae), a new species from the Western Ghats, India. Rheedea 31(1): 18–24. https://dx.doi.org/10.22244/rheedea.2021.31.01.03 LAWAND P.R. 2019. Taxonomic revision of Argyreia Lour. (Convolvulaceae) from India. Ph.D. Thesis (unpublished), Shivaji University, Kolhapur. LAWAND P.R., GAIKWAD S.V., GURAV R.V. & V.B. SHIMPALE 2019. Karyomorphological studies in three species of Argyreia Lour. (Convolvulaceae) from India. The Nucleus 62(1): 71–75. https://doi. org/10.1007/s13237-018-0252-9 MABBERLEY D.J. 2018. Mabberley’s Plant-Book: a portable dictionary of plants, their classification and uses. First South Asia edition. Cambridge University Press, Cambridge. https://doi.org/10.1017/9781316335581 MUÑOZ-RODRÍGUEZ P., CARRUTHERS T., WOOD J.R.I., WILLIAMS B.R.M., WEITEMIER K., KRONMILLER B., GOODWIN Z., SUMADIJAYA A., ANGLIN N.L., FILER D., HARRIS D., RAUSHER M.D., KELLY S., LISTON A. & R.W. SCOTLAND 2019. A taxonomic monograph of Ipomoea integrated across phylogenetic scales. Nature Plants 5: 1136– 1144. https://doi.org/10.1038/s41477-019-0535-4 NAYAR T.S., BEEGAM R.A. & A. SIBI 2014. Flowering Plants of the Western Ghats, India. Volume 2. Jawaharlal Nehru Tropical Botanic Garden. OOSTSTROOM S.J. VAN & R.D. HOOGLAND 1953. Convolvulaceae. In: VAN STEENIS C.G.G.J. (ed.), Flora Malesiana, Series I, Volume IV. NoordhoffKolff, Djakarta. pp. 388–512. POWO 2024 (continuously updated). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Available at: http://www.plantsoftheworldonline. org/ (Accessed on 05.09.2024). QGIS DEVELOPMENT TEAM 2022. Quantum GIS geographic information system. Version 3.32, Lima. SAMPATHKUMAR R. & R.K. AYYANGAR 1981. A critical appraisal of the karyophyletic taxonomy of Convolvulaceae. Journal of Cytology and Genetics 16: 89–99. SHALINI S., SUJANA K.A., ARISDASON W. & D. MAITY 2020. A new species of Argyreia (Convolvulaceae) from the southern Western Ghats, Tamil Nadu, India. Rheedea 30(4): .444–449. https:// dx.doi.org/10.22244/rheedea STAPLES G.W. & P. TRAIPERM 2017. A nomenclatural review of Argyreia (Convolvulaceae). Taxon 66(2): 445–477. https://doi.org/10.12705/662.12 TRAIPERM P. & S. SUDDEE 2020. A new species of Argyreia (Convolvulaceae) from Thailand. PhytoKeys 149: 109–115.