GYMNOSPERMS\tThe gymnosperms are plants in which the ovules are not enclosed by any ovary wall and remain exposed.\tThe giant redwood tree\xa0Sequoia\xa0is one of the tallest tree species belongs to gymnosperms.\tThe roots are generally tap roots, in some genera have fungal association in the form of mycorrhiza (Eg.,Pinus), while in some others (Eg.Cycas) small specialized roots called\xa0coralloid roots\xa0are associated with N2- fixing cyanobacteria.\tThe stems are unbranched (Eg.,Cycas) or branched (Eg.,Pinus).\tThe leaves may be simple or compound, such as pinnate leaves in Cycas and needle-like leaves in conifers.\tThe gymnosperms are heterosporous, haploid microspores and megaspores are produced within sporangia on sporophylls which are arranged spirally along an axis to form compact strobili or cones.\tThe strobili bearing microsporophylls and microsporangia are called\xa0microsporangiate or male strobili.\tThe microspores develop into a male gametophyte which is highly reduced called as a pollen grain.\tThe cones bearing megasporophylls with ovules or megasporangia are called\xa0macrosporangiate or female strobili.