Observations on Ophioglossum eliminatum (Pteridophyta: Ophioglossaceae) with comments on the lowest chromosome number in the genus

Goswami, H. (2012) Observations on Ophioglossum eliminatum (Pteridophyta: Ophioglossaceae) with comments on the lowest chromosome number in the genus. Acta Botanica Hungarica, 54 (3-4). pp. 283-300. ISSN 0236-6495

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Abstract

Population biology data collected during 1995–2009 from more than a dozen localities in Central India have revealed that both the interspecific as well as intraspecific chromosome variations are inherent in many species of Ophioglossum L. The lowest count of chromosome recorded for any plant of Ophioglossum eliminatum Khandelwal et Goswami reported to be n = 30 chromosomes has not been confirmed even in a single spore mother cell or in any mitotically dividing root tip cell. This is emphatically emphasised to be characterised by n = 86±2 chromosomes little lower than originally suggested 90±2 chromosomes. Therefore this is reemphasised that lowest chromosome count for the genus is n = 86, not n = 30 as claimed earlier. Somatic chromosomes from root tip squashes and microtome sections of root tip cells stained with haematoxylin clearly reveal polysomaty (chromosome variations in multiples within the same tissue) in O. eliminatum and O. costatum, which have been probably ignored by earlier workers. Additionally, typical epidermal feature of linear splitting of cells to form several openings in the mesophyll, inherent and expressed only by leaves of O. eliminatum has been found to be a diagnostic trait of the species collected from original localities in Shivpuri forest in Central India and far away in Rajasthan in Western India. As far as known, no living or a fossil leaf has ever shown such natural tearing of the mesophyll tissue.

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