The gymnosperms are the plants in which ovules are not enclosed by any ovary wall. After fertilisation the seeds remain exposed and therefore these plants are called naked-seeded plants. The gymnosperms produce microspores and megaspores which are produced in microsporangia and megasporangia borne on the sporophylls. The sporophylls – microsporophylls and megasporophylls – are arranged spirally on axis to form male and female cones, respectively. The pollen grain germinates and pollen tube releases the male gamete into the ovule, where it fuses with the egg cell in archegonia. Following fertilisation, the zygote develops into embryo and the ovules into seeds.
In Size, gymnosperms range from the tallest known trees to dwarf shrubs. They are represented by cycads, Ginkgo, Conifers, Ephedra, Gnetum, Taxus etc. Structurally gymnosperms are of two types : Conifers with much branching and small simple leaves and Cycads with few branches and large compound leaves.Â
The tallest plant Sequoia wellingtonia (Found in California)Â is a gymnosperm,Â
