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
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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 Wu?rtz, 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
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 Wu?rtz, 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