SPOROGENESIS IN ISOETES L.

Description is given of micro and mega sporogenesis in two species of Isoetes collected from different places in Rajasthan (India). Microsporangia are rare in occurrence in these species and are found only in the inner whorls of sporophylls. A number of variations occur during sporogenesis. The first division of meiosis is karyokinesis while the second is only cytokinesis. Anamolous meiosis results into formation of unequal proportion of sterile and fertile spores. Unsynchronized and irregular cytokinesis produce different sizes of spores. Some of the sporangia are completely devoid of functional sporogenous tissue while in others, majority of spore mother cells produce functional spores.