Revisiting the taxonomy of Exacum courtallense (Gentianaceae) and recognizing E. courtallense var. laxiflorum at the species rank

M.P. GEETHAKUMARY; S. DEEPU; J. KISSLING; A.G. PANDURANGAN

doi:10.11646/phytotaxa.559.2.7

Issue: Vol. 559 No. 2: 23 August 2022

Type: Article

Published: 2022-08-23

DOI: 10.11646/phytotaxa.559.2.7

Page range: 185-192

Abstract views: 43

PDF downloaded: 2

**Revisiting the taxonomy of Exacum courtallense (Gentianaceae) and recognizing E. courtallense var. laxiflorum at the species rank**

M.P. GEETHAKUMARY⁺⁻
S. DEEPU⁺⁻
J. KISSLING⁺⁻
A.G. PANDURANGAN⁺⁻

Plant Systematic and Evolutionary Science Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Karimancode P.O., Thiruvananthapuram, Kerala 695562, India

Plant Systematic and Evolutionary Science Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Karimancode P.O., Thiruvananthapuram, Kerala 695562, India; Forest Ecology Department, Kerala Forest Research Institute, Thrissur, Kerala 680653, India

Institute of biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland

Plant Systematic and Evolutionary Science Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Karimancode P.O., Thiruvananthapuram, Kerala 695562, India; Centre for Innovation in Science and Social Action, Thiruvananthapuram, Kerala 695010, India

Exacum Kerala Tamil Nadu Taxonomy Western Ghats Eudicots

Requires Subscription or Fee PDF (3MB)

Abstract

Morphological, phenological and ecological evidences support the exclusion of Exacum courtallense var. laxiflorum Gamble (synonym: E. courtallense var. bonaccordense M. Mohanan) from E. courtallense Arn. resulting in the establishment of a new species Exacum laxiflorum (Gamble) Geethakumary, Deepu, Kissling & Pandurangan.

References

Arnott, G.A.W. (1839) Exaci species ex peninsula Indica ac ex insula Ceylano. Annales de Sciences Naturelles; Botanique, Sér. 2, 11: 175–176.
Beddome, R.H. (1874) Icones Plantarum Indiae Orientalis. J.B. Pharoah, Madras, pp. 24, t. 118.  https://doi.org/10.5962/bhl.title.92
Blume, C.L. (1826) Bijdragen tot de Flora van Nederlandsch Indië. Lands Drukkerij, Batavia.  https://doi.org/10.5962/bhl.title.115427
Clarke, C.B. (1885) [Exacum lawii]. In: Hooker, J.D., Flora of British India, vol. 4. L. Reeve & Co., London, pp. 98.
Gamble, J.S. (1923) The Flora of Presidency of Madras, Vol. 2. Adlard and Son Ltd., London, 875 pp.
Grisebach, A.H.R. (1845) [Exacum]. In: A.P. de Candolle, Prodromus Systematis Naturalis Regni Vegetabilis, vol. 9. Sumptibus Sociorum Treuttel et Würtz, Paris, pp. 46.  https://doi.org/10.5962/bhl.title.286
Geethakumary, M.P., Pandurangan, A.G., Ravichandran, P. & Deepu, S. (2016a) A new species of Exacum (Gentianaceae) from Western Ghats, India. Phytotaxa 282 (3): 225–229.  https://doi.org/10.11646/phytotaxa.282.3.6
Geethakumary,M.P., K.M.P.Kumar, Pandurangan, A.G. & Deepu, S. (2016b) Exacum keralense (Gentianaceae), a new species from the Western Ghats, India. Botany Letters 163 (4): 429–433.  https://doi.org/10.1080/23818107.2016.1225267
Gopalan, R. (2002) A new species of Exacum L. Gentianaceae from Agasthiyamalai (Pothigai), southern Western Ghats India. Journal of Bombay Natural History Society 99 (2): 271–273.
Henry, A.N. & Swaminathan, M.S. (1983) Rare or new Exacum L. (Gentianaceae) from Southern India. Journal of Bombay Natural History Society 80: 456–459.
IUCN (2012) IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge.
Kissling, J., Yuan, Y.-M., Küpfer, P. & Mansion, G. (2009) The polyphyletic genus Sebaea (Gentianaceae): A step forward in understanding the morphological and karyological evolution of the Exaceae. Molecular Phylogenetics and Evolution 53: 734–748.  https://doi.org/10.1016/j.ympev.2009.07.025
Kissling, J., Zeltner, L., Küpfer, P. & Mansion, G. (2008) Cytogeography of Gentianaceae-Exaceae in Africa, with a special focus on Sebaea: the possible role of dysploidy and polyploidy in the evolution of the tribe. Botanical Journal of the Linnean Society 158: 556–566.  https://doi.org/10.1111/j.1095-8339.2008.00888.x
Klackenberg, J. (1985) The genus Exacum (Gentianaceae). Opera Botanica 84: 1–144.
Linnaeus, C. (1753) Species Plantarum. Vol. 1. Impensis Laurentii Salvii, Stockholm, 560 pp.
Mallikarjuna, M.B., Scheriff, A. & Krishnappa, D.G. (1987) Chromosome number reports XCVII (ed. A. Löve). Taxon 36: 766–767.  https://doi.org/10.1002/j.1996-8175.1987.tb00894.x
Mohanan, M. (1994) [Exacum]. In: Mohanan, M. & Henry, A.N. (Eds.) Flora of Thiruvananthapuram. Botanical Survey of India, Calcutta, p. 305.
POWO (2019). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/ (Accessed 11 May 2021).
Roxburgh, W. (1832) [Exacum tetragonum]. In: Roxbourgh, W & Carey, W., Flora indica, vol. 1. Serampore, pp. 398.  https://doi.org/10.5962/bhl.title.590
Sasidharan, N. (2004) Biodiversity Documentation for Kerala. Part 6: Flowering Plants. Kerala Forest Research Institute, Kerala, 702 pp.
Shahina, P.M. & Nampy, S. (2016) A taxonomic revision of Exacum L. (Gentianaceae - Exaceae) in South India. International Journal of Applied Research 4 (3): 1656−1683. [https://www.journalijar.com/article/8728/a-taxonomic-revision-of-exacum-l.-(gentianaceae---exaceae)-in-south-india/]
Theirs, B. (2021 [continuously updated]) Index Herbariorum: A global Directory of Public Herbaria and Associated Staff. New York Botanical Garden’s Virtual Herbarium. Available from: http://sweetgum.nybg.org/science/ih/ (Accessed 15 August 2021).
Yuan, Y.M., Wohlhauser, S., Moller, M., Klackenberg, J, Callmander, M. & Kupfer, P. (2005) Phylogeny and biogeography of Exacum (Gentianaceae): a disjunctive distribution in the Indian Ocean Basin resulted from long-distance dispersal and extensive radiation. Systematic Biology 54: 21–34.  https://doi.org/10.1080/10635150590905867