Isoetes Pantii (Isoetaceae:Pteridophyta) - A Review

The taxon, Isoetes pantii H.K. Goswami & B.S. Arya discovered in 1970, possess genetically inherent features of development of three types of morphologically distinct microspores, (monolete, alete and trilete) as well as large megaspores within one and the same microsporangium, a feature never known, even today, in any species of the genus Isoetes. Follow up studies on morphological, chromosomal and biochemical approaches published on different species of Isoetes in Central India over four decades have repeatedly confirmed these findings and we strongly reestablish here the integrity of the species as a unique taxon of the genus. Isoetes pantii is also the only species to possess 2n=36, 48 chromosomes and related plant populations in the Narsinghgarh area (Madhya Pradesh, India) have shown 2n=60 and 2n=72 chromosomes indicating thereby that the new line of chromosome evolution of n=12 series have probably evolved through this species as already suggested elsewhere.