Apogamous Isoetes coromandelina L.f. (Isoetaceae) with asynaptic meiosis


  • V. Irudayaraj Department of Botany, St. Xavier’s College (Autonomous), Palayamkottai, Tamil Nadu – 627002
  • A. Benniamin Botanical Survey of India, Western Regional Centre, Pune
  • S. Arokia Raj Department of Botany, St. Xavier’s College (Autonomous), Palayamkottai, Tamil Nadu – 627002




Isoetes coromandelina, asynaptic meiosis, apogamy


This cytological study on Isoetes coromandelina L.f (Isoetaceae) from Tirunelveli District, Tamil Nadu, South India shows the presence of twenty two individual chromosomes along with a fragment (n=2n=22+1) during meiosis in megaspore mother cells without the presence of any bivalent. Cytomixis between two megaspores is very common, resulting in the formation of a high percentage of abortive spores. The present material is of an apogamous taxon with asynaptic Meiosis as reported by Abraham and Ninan from Kerala and Karnataka.


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Abraham A, Ninan, CA. 1958. Cytology of Isoetes. Curr. Sci. 27(2): 60-61.

Ansari, H. A., Ellison, N. W., Verry, I. M. & Williams, W. M. 2022. Asynapsis and unreduced gamete formation in a Trifolium interspecific hybrid. BMC Plant Biology, 22: 14.

Bell, P. R. 1960. The morphology and cytology of sporogenesis of Trichomanes proliferum Bl. New Phytol. 59: 53.

Bobak M, Herich R. 1978. Cytomixis as a manifestation of pathological changes after the application of trifluraline. Nucleus India, 21:22-26.

Braithwaite, A. F. 1964. A new type of apogamy in ferns. New Phytologist, 63(3): 293-305.

Fraser-Jenkins CR, Gandhi KN, Kholia, BS, Benniamin A. 2017. An Annotated Checklist of Indian Pteridophytes Part 1. Lycopodiaceae to Thelypteridaceae. Bishen Singh & Mahendra Pal Singh, Dehra Dun.

Ghanima AM, Talaat AA. 2003. Cytomixis and its possible evolutionary role in a Kuwaiti population of Diplotaxis harra (Brassicaceae). Bot. J. Linn. Soc. 143: 169-175.

Heng-Chang W, Li JQ, He ZC. 2007. Irregular meiotic behavior in Isoetes sinensis (Isoetaceae), a rare and endangered fern in China. Caryologia, 60(4) 358-363.

Hoot SB, Napier NS, Taylor WC. 2004. Revealing unknown or extinct lineages within Isoëtes (Isoëtaceae) using DNA sequences from hybrids. American J. Bot. 91(6): 899-904.

Jongedijk E, Ramanna MS, Sawor Z, Hermsen JG. 1991. Formation of first division restitution (FDR) 2n-megaspores through pseudohomotypic division in ds-1 (desynapsis) mutants of diploid potato: routine production of tetraploid progeny from 2xFDR × 2xFDR crosses. Theor Appl Genet. 82(5):645-56.

Kuriachan PI, Ninan CA. 1974 a. Karyomorphology of a triploid Isoetes coromandelina with a note on the karyotype evolution in the species. New Bot. 1: 160-169.

Kuriachan PI, Ninan CA. 1974 b. Trisomy and translocations in Isoetes coromandelina L. pp. 307-317. In P. Kachroo (ed.), Advancing Frontiers in Cytogenetics. Hindustan Publ. Co., Dehli.

Liu HM, Dyer RJ, Guo ZH, Meng Z, Li JJ, Schneider H. 2012. The eveolutionary dynamics of apomixes in ferns: A case study from polystichoid ferns. J. Bot. Article ID 510478.

Manickam VS, Irudayaraj V. 1992. Pteridophyte Flora of the Western Ghats, South India. BI Publications, Pvt. Ltd. New Delhi.

Manton, I & Sledge, WA. 1954. Observations on the cytology and taxonomy of the pteridophyte flora of Ceylon. Phi. Trans. B238, 127.

Mehra, PN & Singh, G. 1957. Cytology of Hymenophyllaceae. J. Genet. 55: 379.

Molur S, Smith KG, Daniel BA, Darwall WRT. (Compilers). 2011. The status and distribution of freshwater biodiversity in the Western Ghats, India. IUCN, Cambridge, UK and Gland, Switzerland.

Morisset P. 1978. Cytomixis in pollen mother cell of Ononis (Leguminosae). Can. J. Genet. Cytol., 20: 383-388.

Nirmala A, Rao PN. 1996. Genesis of chromosomal numerical mosaicism in higher plants. Nucleus, 39: 151-175.

Pant DD, Srivastava GK, 1965. Cytology and reproduction of some Indian species of Isoetes. Cytologia, 30: 239-251.

Pryer KM, Schneider H, Smith AR, Cranfil LR, Wolf PG, Hunt JS, Sipes SD. 2001. Horsetails and ferns are a monophyletic group and the closest living relatives to seed plants. Nature, 409: 618-622.

Pryer KM, Schuettpelz E, Wolf PG, Schneider, H, Smith AR, Cranfill R. 2004. Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences. Amer. J. Bot. 91(10): 1562-1598.

Smith AR, Pryer KM, Schuettpelz E, Korall P, Schneider H, Wolf PG. 2006. A classification for extant ferns. Taxon 55(3): 705-731.

Retallack GJ. 1997. “Earliest Triassic Origin of Isoetes and Quillwort Evolutionary Radiation.” Journal of Paleontology, 71(3): 500-521.

Taylor WC, Hickey RJ. 1992. Habitat, evolution, and speciation in Isoetes. Ann. Miss. Bot. Gard. 79(3): 613-622.




How to Cite

Irudayaraj, V., Benniamin, A., & Arokia Raj, S. (2024). Apogamous Isoetes coromandelina L.f. (Isoetaceae) with asynaptic meiosis. Caryologia, 76(4), 51–57. https://doi.org/10.36253/caryologia-2222